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1994-1997 Ford 7.3 L Powerstroke – DIT Engine Information

Description

Reference Number(s): 97-15A-1, Date of Issue:  August 4, 1997

FORD: 1994-1996 F-47; 1994-1997 F SUPER DUTY, F-250, F-350; 1995-1996 F-250 CREW CAB, F-350 CREW CAB; 1995-1997 ECONOLINE, E-250, E-350

Details

INTRODUCTION

This 7.3L DIT Powerstroke Diagnostic Aide is being published in order to assist the dealer service technician with diagnosing driveability concerns. TSBs and OASIS messages have been included addressing several diagnostic procedures for driveability symptoms. The diagnostic aide is intended to condense TSBs and OASIS messages into one comprehensive manual for the technician. It is also intended to be a reference guide and a supplement to the PC/ED Manual (Powertrain Control/Emissions Diagnosis).

Using the flowcharts and recommendations in this manual should provide clear direction to the service technician, and should also assist in diagnosis, reduce repair time, repeat field repairs, and reduce owner down time.

This TSB is not a substitute for attending a comprehensive training class.

SECTION 00-00: POWER STROKE DIESEL ENGINE – 97-15A 7.3L DI TURBO WORKSHOP MANUAL

TABLE OF CONTENTS

  1. MECHANICAL DIAGNOSTIC FORM INFORMATION
  2. HARD START/NO START DIAGNOSTIC PROCEDURES
  3. PERFORMANCE DIAGNOSTIC PROCEDURES
  4. ELECTRONIC CONTROL SYSTEM DIAGNOSTICS
  5. SUPPLEMENTAL DIAGNOSTIC PROCEDURES
  6. SYMPTOM FLOWCHARTS

MECHANICAL DIAGNOSTIC FORM INFORMATION

Instructions For Using The Mechanical Diagnostic Form

The mechanical diagnostic form is intended to be the starting point for diagnostics for most engine related problems. It addresses diagnostic procedures for Hard Start/No Start conditions as well as Performance concerns. It is also intended to a be used as a diagnostic and warranty record for the vehicle.

Prior to removal and replacement of the parts listed below, it is required that the appropriate sections of the mechanical diagnostic form be completed to secure warranty reimbursement.

Structure:  The top of the form provides the technician with areas to enter data that will identify the customer, dealer, model year, engine and vehicle configuration and what the customer’s complaint is.

Customer Name:  Required for warranty purposes.

Dealer Name and Location:  Required for warranty purposes.

1863 Claim Number:  Required for warranty purposes.

Date:  Required for warranty purposes.

Model Year:  Significant changes in PCM calibration and diagnostics have occurred between the 1994 and 1995 PCM calibration. Calibrations for 1994 utilize a STAR II tester and connect to the STI and STO connector located under the hood. PCM calibrations for 1995 utilize the NGS tool (New Generation Star Tester) which has an under dash connection and is capable of commanding diagnostic tests and monitoring PID’s on the diagnostic data link. Trucks built in 1995 do not have the under hood connector for the STAR II tester. Trucks built in 1994 have the connector under the dash for the NGS tool. The connector is not functional for diagnostics unless the PCM has been reflashed to a 1995 calibration. If a 1994 vehicle had been reflashed to a 1995 calibration, the STI and STO connector under the hood will not function with the STAR II tester.

Vehicle Serial Number:  The tenth position of the vehicle serial number (VIN) indicates model year.

  1. R=1994
  2. S=1995
  3. T=1996
  4. V=1997

Engine Serial Number:  The engine serial number is located on the calibration tag applied to the reservoir and also is stamped on the cylinder block on a pad located near the rear of the oil cooler.

Odometer:  Required for warranty purposes.

Chassis Style:  Helpful for evaluation of performance or fuel consumption complaints.

Vehicle GVW:  Helpful for evaluation of performance or fuel consumption complaints.

Transmission:  Helpful for evaluation of performance or fuel consumption complaints. Different PCM calibrations are required for manual and automatic transmissions.

Ambient Temperature:  Glow plug on time and exhaust back pressure operation are dependent on ambient temperature.

Customer Complaints:  Detailed description of customers concerns including conditions required to make the problem occur.

The left side of the form provides the technician with the procedures to diagnose a Hard Start/No Start complaint. Each test should be completed and the test values entered into each box.

The right side of the form provides the technician with the procedures to diagnose a performance complaint (examples listed below).

Each test should be completed and the test values entered into each box.

The bottom of the form allows for entry of repairs performed to correct the problem, the names of the parts replaced, the part numbers replaced as well as the serial numbers of the defective items.

Diagnose 7-3, Save $10 off $50, Use Code TENOFF73

HARD START/NO START DIAGNOSTIC PROCEDURES

1. Sufficient Clean Fuel

FUEL TANK CHECK
Method Checks
Visual Front Tank, Rear Tank
Purpose
 

The purpose of this test is to determine if the fuel system is getting sufficient clean fuel to start and run the engine.

Test Procedure

Route a hose from the fuel drain tube to a clear container and open the drain. Crank the engine and observe the fuel flowing into the container. Stop cranking the engine when the container is half full.

NOTE: If, when attempting to drain the fuel filter, no flow occurs by opening the valve, the lid should be loosened one (1) turn. Loosening the lid will allow air to enter the top of the filter and fuel/water to drain from the bottom. This should only be done with the engine not running.

Observe the WATER IN FUEL light while cranking the engine. If the light is illuminated, the fuel may be contaminated with water.

Fuel flow out of the drain tube should be a steady stream. Insufficient flow could indicate fuel supply or fuel system problems.

Inspect fuel in container. The fuel should be clear or straw colored, but not cloudy and should be free of water and contaminates. Check fuel odor for presence of other fuels, such as gasoline.

Sufficient Clean Fuel

If engine oil is present in the fuel , it may indicate an injector “O” ring leak and subsequent loss of rail pressure. If that is suspected, check injector control pressure during engine cranking (Test 8C).

If the fuel filter has not been serviced for a prolonged period of time or hasn’t been drained recently, some sediment and water may be present in the fuel sample. A second sample may be required to determine fuel quality.

Possible Causes (Low Or No Fuel Flow)
  • No fuel in tank.
  • If equipped with a fuel incline valve, it could be shut off. If vehicle is equipped with dual fuel tanks the fuel transfer valve could be faulty.
  • Fuel supply line from tank(s) could be broken or crimped.
  • Fuel could be jelled (most likely in cold weather with #2 fuel) or the pickup tube screen in tank could be clogged.

Cloudy fuel indicates that the fuel may not be a suitable grade for cold temperatures, excessive water or contaminants may indicate that the tank and fuel system may need to be flushed and cleaned.

Tools Required
  1. Clear container approximately 1 quart.

Visual Engine Chassis Inspection

2. Visual Engine Chassis Inspection

FUEL, OIL, COOLANT, ELECTRICAL
Method Check
Visual  
Purpose

This is a visual inspection to verify the general condition of the engine and to look for obvious causes of hard or no start conditions.

Test Procedure

Inspect fuel system including tank and lines for kinks, bends and/or leakage. Check high pressure oil lines and high pressure pump in engine “V” for oil leaks. Inspect for coolant leaks at radiator and heater hoses and check coolant level. Inspect wiring for correct routing and verify no rubbing or chafing has occurred. Inspect the in-line 42-way, IDM, PCM, sensor and actuator connectors to ensure that they are completely seated and in good condition.

Possible Causes
  • Loose or leaking fuel supply lines may cause fuel system to lose prime.
  • Kinked or blocked fuel supply lines will create fuel restriction.
  • Fuel or oil leaks could contribute to no start conditions.
  • Coolant leaks may indicate potentially serious engine problems.
  • Electronic connectors may be damaged or not installed properly, potentially causing a no start condition. (The CMP sensor and the IPR valve are the two most critical electronic sensors/actuators to inspect in no start situations.)
Tools Required
  1. Inspection light.

Check Engine Oil Level

3. Check Engine Oil Level
  • Check for contaminants (fuel, coolant)
  • Correct grade/Viscosity
  • Miles/Hours on oil, correct level
  • Check level in reservoir

ENGINE OIL LEVEL CHECK
Method Check
Visual  
Purpose

To determine if there is enough oil or oil of sufficient quality to operate the injectors.

Test Procedure

Check oil level with oil gauge when vehicle is on level ground. If there is no oil or very little oil in the crankcase, the injectors will not operate.

If the oil level exceeds the recommended amount, it is possible the engine was incorrectly serviced or fuel is diluting the oil and filling the crankcase. Usually if a substantial amount of fuel is in the oil, the oil will have a fuel odor.

Inspect oil for color. A milky white oil indicates possible coolant contamination and will have an ethylene glycol odor.

Check service records for correct oil type and viscosity for the vehicle operating temperature. Single grade or 15W 40 oil is recommended for cold ambient temperatures. Oil that has had extended drain intervals will have increased viscosity (become thicker) and will make engine cranking more difficult and starting less reliable at temperatures below freezing. Refer to the lube oil chart below to select the correct (viscosity) oil to use for the temperature condition(s) the engine will be operating in. Use CG-4/SH rated oil.

Lube Oil Chart

The oil level reservoir should also be checked. Remove the inspection plug in top of reservoir and check to see if the oil level in the reservoir is within one inch from the bottom of the inspection plug. (A reservoir that drains back after the engine has not been operated for a period of time can cause a hard start and stall condition.) Filling the reservoir will allow the system to prime faster, thereby facilitating starting.

Checking Oil Level In Reservoir
Possible Causes
  • Oil level low – Oil leak, oil consumption, incorrect servicing.
  • Oil level high – Incorrect servicing, fuel dilution from lift pump, fuel dilution from loose injectors.
  • Oil contamination with coolant – Oil cooler, head gasket, porosity.
  • Low reservoir level – Engine built dry (not pressure lubed), prolonged period of not running, leaking check valve in high pressure pump (1994-95 model years only). Excessive cranking without starting.
Tools Required
  1. 1/4 inch drive ratchet or breaker bar to remove inspection plug.

Intake/Exhaust Restriction

4. Intake/Exhaust Restriction
  • Inspect air filter and ducts – exhaust system
  • Inspect exhaust back pressure device

INTAKE/EXHAUST RESTRICTION CHECK
Method Check
Visual  
Purpose

This is a visual inspection to help determine if an intake or exhaust restriction is contributing to a no start or hard start condition. If the engine does start with high inlet or exhaust restriction, a considerable amount of black/blue smoke is produced.

Test Procedure

Inspect the air cleaner inlet and ducting to assure that it is not blocked or collapsed. Inspect air cleaner housing and filter for proper installation. Inspect the filter minder ( to assure intake restriction is below the red marks.

Inspect the exhaust back pressure device bell crank during cranking and assure it is not closing. If the tang is positioned as shown in the exhaust (butterfly) valve is opened. Inspect the exhaust system for damaged or blocked pipes.

Possible Causes
  • Snow, plastic bags or other foreign material may restrict air flow at the air cleaner inlet.
  • Misrouted air cleaner ducting may collapse when the hood is shut.
  • On engines recently repaired, rags or cap plugs may have been inadvertently left in an intake pipe.
  • The exhaust back pressure device may be closing during cranking or stuck closed.
  • The tailpipe or muffler may have collapsed or been damaged or the catalytic converter is clogged.
Tools Required
  1. None.

Perform KOEO Demand Self Test

5. Perform KOEO Test
  • Diagnostic Trouble Codes set during this test are current faults

Pass Code = P1111 

Diagnostic Trouble Codes _____

Purpose

To determine if the PCM has detected any fault conditions that may cause a hard or no start condition.

Test Procedure

Connect the NGS tool to the diagnostic connector under the dash. Turn off all accessories. Turn the ignition key “ON”.

  • Perform the necessary vehicle preparation and visual inspection.
  • Select Vehicle and Engine Selection menu.
  • Select year, engine, and model.
  • Select DIAGNOSTIC DATA LINK.
  • Select PCM – POWERTRAIN CONTROL MODULE.
  • Select DIAGNOSTIC TEST MODES.
  • Select KOEO On Demand Self Test.
  • Follow operating instructions from the menu.
  • Record DTCs and follow appropriate pinpoint test.

If any fault codes other than the PASS code sequence of P1111 is transmitted or if no codes are transmitted, refer to Diagnostic Trouble Code Description Chart in Scan Diagnostic Test section for appropriate pinpoint test.

NOTE: All current faults must be fixed before proceeding.
NOTE: IDM detected faults transmitted during this test are not current faults and have been set previously. IDM faults can only be cleared through the “retrieve continuous fault” menu through the C-ALL command. (IDM detected faults will not be displayed when retrieving continuous fault codes.)
New Generation Star Hookup With Adapter Cable Assembly
Possible Causes

The most likely PCM detectable faults that will indicate the cause of a no start or hard start condition are:

  • CMP sensor inactive faults.
  • IPR output circuit check fault.
  • FDCS and CI output circuit check faults.
Tools Required
  1. NGS Scan Tool.

Retrieve/Clear Continuous DTCs

6. Retrieve Continuous Trouble Codes
  • Diagnostic Trouble Codes retrieved during this test are historical faults.

Pass Code = P1111 

Diagnostic Trouble Codes _____

Purpose

To determine if the PCM has detected any historical or intermittent fault conditions that may cause a hard start/no start symptom. The condition that caused a continuous code may no longer exist.

Test Procedure
  • Turn the ignition key “ON.”
  • Select RETRIEVE/CLEAR CONTINUOUS DTCs.
  • Follow operating instructions from the menu.
  • Record DTCs and follow appropriate pinpoint test.
  • Continuous DTCs must be cleared after repair is made.
Tools Required
  1. NGS Scan Tool.

NOTE: Special instructions requires to clear idm trouble codes.

  • Ignition key “ON.”
  • Record IDM trouble codes stored in “KOEO ON DEMAND SELF TEST” mode.
  • Access “RETRIEVE/CLEAR CONTINUOUS DTCs” from NGS menu to clear IDM trouble codes from memory. IDM detected faults will not be displayed during this test, but can only be cleared from this menu.
  • Push “C-ALL” button on NGS tool.
  • IDM trouble codes are now cleared from memory.

KOEO Injector Electrical Self Test (Buzz Test)

NOTE: If Unable To Perform KOEO Injector Buzz Test, Disconnect IDM Connector And Injector High And Low Side For Short To Ground Condition Or Open Circuits.
7. KOEO Injector Electrical Self Test
  • Select Injector Electrical Self-Test from the NGS test menu.
  • All injectors will momentarily buzz, then individual injectors will buzz in sequence 1 through 8.
  • Diagnostic Trouble Codes will be transmitted after test is completed.

Pass Code = P1111 

Injector Trouble Codes _____

Purpose

To determine if the injector solenoids and poppet valves are operating properly by buzzing all injectors together and then each injector in numerical sequence (1 through 8). Refer to for cylinder/injector location.

Test Procedure

Connect NGS scan tool to diagnostic connector under the dash. Select injector electrical self test from the NGS menu screen and follow the operating instructions on the screen.

NOTE: IDM Diagnostic Trouble Codes Will Display In The KOEO ON DEMAND SELF TEST MODE. (Accessing KOEO TEST MODE Is Required To Retrieve Fault Codes.) See Special Instructions For Clearing IDM Trouble Codes. The Instructions Are Listed With The KOEO On Demand Self Test Instructions.
Possible Causes
  • Open injector wire.
  • Bad injector connector.
  • Shorted wire or connector.
  • Open injector solenoid.
  • Defective IDM.
Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500 or equivalent.
7.3L DI Cylinder/Injector Location
New Generation Star Hookup With Adapter Cable Assembly

Check VPWR During Cranking

8. NGS Tool – Data List Monitoring
  • Select the parameters indicated from the NGS parameter list and monitor while cranking engine.

VPWR CHECK DURING CRANKING
Parameter Spec Measurement
VPWR 7 volt minimum  
RPM 100 RPM minimum  
ICP 500 PSI or 1 volt min.  
FUEL PW 1 mS to 6 mS  
Purpose

To verify PCM power-up during cranking. Lack of power to PCM can cause a no start condition as well as fault code loss.

Test Procedure

Install NGS scan tool. Access VPWR PID on NGS scan tool and monitor while cranking the engine. If the NGS tool blanks out or resets during this test, battery voltage is most likely low.

Possible Causes
  • Low battery voltage.
  • Charging system problem.
  • Power circuits or grounds to PCM

Refer to Pinpoint Test A for diagnosis.

Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500 or equivalent.
New Generation Star Hookup With Adapter Cable Assembly

Check RPM Signal While Cranking

8. NGS Tool – Data List Monitoring
  • Select the parameters indicated from the NGS parameter list and monitor while cranking engine.

RPM SIGNAL CHECK WHILE CRANKING
Parameter Spec. Measurement
VPWR 7 volt minimum  
RPM 100 RPM minimum  
ICP 500 PSI or 1 volt min.  
FUEL PW 1 mS to 6 mS  
Purpose

To determine if the CMP (Camshaft Position Sensor) circuit is functioning and if sufficient engine RPM is present.

Test Procedure

Install the NGS scan tool. Access the RPM PID on NGS scan tool and monitor RPM reading while cranking the engine. NGS will read RPM if PCM is receiving a CMP signal.

Possible Causes
  • Faulty wire harness connection.
  • Poor CMP ground connection.
  • Incorrect CMP sensor to timing disk spacing.
  • Defective CMP sensor.

Refer to Pinpoint Test G for CMP sensor diagnosis.

Monitor ICP (Injection Control Pressure) While Cranking

8. NGS Tool – Data List Monitoring
  • Select the parameters indicated from the NGS parameter list and monitor while cranking engine.

ICP MONITOR WHILE CRANKING
Parameter Spec. Measurement
VPWR 7 volt minimum  
RPM 100 RPM minimum  
ICP 500 PSI or 1 volt min.  
FUEL PW 1 mS to 6 mS  
Purpose

To determine if the injection control pressure system can supply enough injection control pressure to sustain starting.

Test Procedure

Install the NGS scan tool. Access the ICP PID on NGS scan tool and monitor ICP reading while cranking the engine.

NOTE: CMP signal is required before IPC pressure is allowed above approximately 800 PSI.

If value does not meet the minimum specification, the injectors are not being enabled by the PCM because of insufficient pressure.

Possible Causes
  • ICP system leak.
  • Oil reservoir level low.
  • Injection Pressure Regulator valve failure.
  • Defective high pressure pump.
Instructions For Determining Cause Of No/Low Injection Pressure

Remove the inspection plug in the top of the oil reservoir to help determine if the reservoir is full. A reservoir that drains back after the engine has not been operated for a long period of time can cause a hard start condition.

Checking Oil Level In Reservoir

High Pressure Leakage Test

High Pressure Leakage Test
  • Remove high pressure hose from right cyl. head and plug hose.
  • Measure ICP voltage during cranking.

HIGH PRESSURE LEAKAGE TEST – RIGHT HEAD
Instrument Spec. Check
DVOM +87, -91 1 to 4 volts  

If engine starts leak is in right head. 

  • Remove high pressure hose from left cyl. head plug hose. Install right side hose.
  • Install ICP sensor in left side adapter.

HIGH PRESSURE LEAKAGE TEST – LEFT HEAD
Instrument Spec. Check
DVOM +87, -91 1 to 4 volts  

If engine starts leak is in left head. 

  • Install plug in both hoses, measure ICP.

HIGH PRESSURE LEAKAGE TEST – BOTH HEADS
Instrument Spec. Check
DVOM +87, -91 1 to 4 volts  

If unable to maintain pressure with both heads blocked, change IPR valve and retest. 

Test Procedure: Right Cylinder Head Check

Remove the high pressure hose from the right cylinder head. Use a fuel/oil/turbo protector cap set (use steel caps and fittings only) , Tool Number D94T-6600-A and install into the high pressure hose to block it off. Connect ICP sensor cable T94-50-A to the ICP sensor. Connect a DVOM between signal ground and ICP signal wires on sensor cable, crank the engine and monitor the signal. The DVOM should read 1 to 4 volts.

CAUTION: The engine may start!

If the engine starts or if the ICP pressure is now within specifications, the injection control pressure leak has been isolated to the right cylinder head. Inspect the fuel to see if oil is in the fuel. If no oil is present in the fuel, remove the valve cover, crank the engine and inspect the injector body and injector bore areas for leakage.

CAUTION: CAUTION: Oil is under high pressure!
Test Procedure: Left Cylinder Head Check

Install right side high pressure hose to the cylinder head. (Remove the left side high pressure hose and install ICP adapter plug into hose. Remove ICP sensor and install it in the end of the adapter plug. Connect ICP sensor cable T94-50-A to the ICP sensor. Connect a DVOM between signal ground and ICP signal wires on sensor cable. Crank the engine and monitor the signal. The DVOM should read 1 to 4 volts.

CAUTION: The engine may start!

If engine starts or if ICP is now within specification, the injection control pressure leak has been isolated to the left cylinder head. If the engine does not start continue.

Isolating Left Cylinder Head
IPR And High Press Pump Test (

If injection control pressure is still low after isolating both cylinder heads, use the plain flare plug to block the right high pressure hose and crank the engine. (Leave ICP sensor and adapter in left hose.) This has effectively deadheaded the high pressure pump. If the pressure is still not developed, inspect the IPR (Injection Pressure Regulator Valve) for debris and/or replace with a known good valve and retest. If a low pressure condition still exists, the problem is most likely with the high pressure pump or the high pressure pump drive gear.

IPR And High Press Pump Test

Check Fuel Pulse Width (Fuel PW) While Cranking

8. NGS Tool – Data List Monitoring
  • Select the parameters indicated from the NGS parameter list and monitor while cranking engine.

FUEL PULSE WIDTH CHECK WHILE CRANKING
Parameter Spec. Measurement
VPWR 7 volt minimum  
RPM 100 RPM minimum  
ICP 500 PSI or 1 volt min.  
FUEL PW 1 mS to 6 mS  
Purpose

To verify that the Fuel Demand Command Signal (FDCS) system is functioning correctly and that the engine and control system are synchronized.

Test Procedure

Install the NGS scan tool. Access the FUEL PW PID on the NGS scan tool and monitor while cranking the engine.

No fuel command signal when ICP, RPM and VPWR signals are correct usually indicates a loss of CMP sync signal.

A 1 to 6 mS Fuel PW will be sent by the PCM (Powertrain Control Module) to the IDM (Injector Drive Module) when a sync pulse has been received from the CMP (Camshaft Position Sensor) and when sufficient ICP (Injection Control Pressure) is present. A .42 mS Fuel PW (a no fueling pulse) will be sent by the PCM when a sync pulse has been received from the CMP sensor and if insufficient ICP pressure is present. This .42 mS pulse width will not allow injectors to be enabled, but does keep the IDM and PCM synchronized until sufficient ICP is realized.

Refer to Pinpoint Test G for CMP sensor diagnosis.

Possible Causes
  • Fuel Demand Command Signal circuitry.
  • Defective PCM.
  • Defective IDM.

Tandem Fuel Pump Pressure

9. Tandem Fuel Pump Pressure
  • Measure at regulator block.
  • Minimum 100 RPM crank speed for 20 sec.

FRONT TANK
Instrument Spec. Measurement
0-160 PSI Gauge 20 PSI min.  

REAR TANK
Instrument Spec. Measurement
0-160 PSI Gauge 20 PSI min.  

If failed Test 9, change fuel filter and retest.

Purpose

To determine if there is sufficient fuel pressure for starting the engine.

Test Procedure

Connect line for 160 psi gauge to the Schrader adapter mounted on the fuel filter regulator block on the side of the fuel filter housing. Crank engine at 100 RPM minimum and measure maximum fuel pressure.

Measuring Tandem Pump Pressure
Possible Causes
  • A fuel filter may cause high restriction and low fuel pressure due to dirt of fuel jelling in cold ambient temperatures. Replace fuel filter and retest.
    NOTE: It may take more than one crank to purge the air out of the fuel system.
  • Debris in the fuel regulator valve will cause low fuel pressure. Disassemble, inspect and clean.
  • A kinked or severely bent fuel line or blockage at the pickup tube may cause restriction and therefore low fuel pressure.
  • A loose fuel line on the suction side of the fuel system may cause air to be ingested into the system and may cause low fuel pressure.
  • The fuel pump could have internal damage, e.g. ruptured diaphragm, seized plunger or leaking check valves.
Tools Required
  1. 0 to 160 PSI fuel pressure gauge, appropriate line with 1/8 inch NPT fitting or schrader valve connector.

Glow Plug System Operation

10. Glow Plug System Operation

Relay Operation

  • Install a voltmeter to the flow plug feed terminal (2 wire terminal).
  • Turn key to run position, measure “ON” time.
  • Verify sufficient glow plug “ON” time and voltage (dependent on oil temperature and altitude).
    RELAY OPERATION
    9 – 12 Volts Spec. Measurement
    Relay On Time 10-120 seconds  
  • If no voltage present, measure voltage at power supply terminal on relay (single large terminal).
  • Power is supplied via two fusible link wires connected to starter relay.

Glow Plug Operation

  • Measure glow plug resistance to Bat. Ground.
  • Remove all glow plug/injector connectors.
  • Measure GP harness resistance to Relay.

GLOW PLUG RESISTANCE MEASUREMENTS
Glow Plug Number Glow Plug to Ground 0.1 to 2 ohms Connector to Relay 0 to 1 ohm
#1    
#3    
#5    
#7    
#2    
#4    
#6    
#8    
Purpose

To determine if the glow plug system operation is sufficient to permit starting.

A heavy duty glow plug relay was introduced in March 1996.

Loose connections at the high current connections on the glow plug relay can lead to failure of the relay (over-heated terminals.)

If the glow plug relay is replaced, the nuts must be tightened to 70 lb-in.

NOTE: OBD II (California) diagnostics are at the end of this bulletin.
Test Procedure: Relay Operation

Connect a DVOM on the glow plug feed side of the glow plug relay (large stud with two wires connected). Turn the ignition key to the “ON” position, but do not attempt to start engine. Note the time in seconds from when the key is turned “ON” and the glow plug relay energizes until the glow relay de-energizes. The glow plug relay will make a loud click noise which is easily heard when it energizes and de-energizes. The dome light will dim and the dash voltmeter will dip when glow plugs are drawing current form the battery. “ON” time will be affected by engine temperature, battery condition and vehicle altitude. The voltage at the glow plug feed terminal may vary from 9 to 12 volts depending upon battery condition.

Measuring Glow Plug/Relay “ON” Time

If battery voltage not present, check for B+ at power supply terminal (terminal with single large wire). Power for glow plug power supply is supplied from starter relay through two fusible links at solenoid.

Test Procedure: Glow Plug Operation

Disconnect all of the glow plug/injector connectors from both valve cover gaskets. (4 connectors) With the pigtail harness adapter installed (PN 01-00935) measure glow plug resistance to ground (preferably B-). A resistance measurement of .1 to 2 ohms indicates a good glow plug.

Measuring Glow Plug Resistance To Ground (B-)
Test Procedure: Glow Plug Harness Continuity
NOTE: Incorrect measurements will result if all glow/injector connectors to valve cover are not disconnected. (4 connectors)

Measure for continuity from the connector harness to the glow plug feed terminal on the glow plug relay. Resistance should be less than 5 ohms.

Measuring Glow Plug Harness Resistance To Relay
Possible Causes

Insufficient glow plug “ON” time will not allow enough heat to accumulate in the combustion chamber to easily facilitate starting. If the glow plug system does not turn “ON, ” and remain on for 10-120 seconds, the problem may be a:

  • Faulty wire harness connection.
  • Poor ground connection.
  • Defective glow plug relay.

If the glow plug resistance to ground is high, the most likely causes may be:

  • Open UVC (under valve cover) harness.
  • Open glow plug.
Tools Required
  1. Rotunda DVOM 105-00050, pigtail connector (PN 014-00935), stop watch or equivalent.

PERFORMANCE DIAGNOSTIC PROCEDURES

Instructions For Using The Mechanical Diagnostic Form

The mechanical diagnostic form is intended to be the starting point for diagnostics for most engine related problems. It addresses diagnostic procedures for Hard Start/No Start conditions as well as Performance concerns. It is also intended to be used as a diagnostic and warranty record for the vehicle.

Prior to removal and replacement of the parts listed below, it is required that the appropriate sections of the mechanical diagnostic form be completed to secure warranty reimbursement.

  • Injectors (9E527)
  • Injection control pressure regulator (9C968)
  • High pressure pump assembly (9A543)
  • Turbocharger/pedestal assembly (9350)
  • Fuel pump (9350) Injector Drive Module (12B599)
  • Powertrain control module (12A650)

Structure:  The top of the form provides the technician with areas to enter data that will identify the customer, dealer, model year, engine and vehicle configuration and what the customer’s complaint is.

Customer Name:  Required for warranty purposes.

Dealer Name and Location:  Required for warranty purposes.

1863 Claim Number:  Required for warranty purposes.

Date:  Required for warranty purposes.

Model Year:  Significant changes in PCM calibration and diagnostics have occurred between the 1994 and 1995 PCM calibration. Calibrations for 1994 utilize a STAR II tester and connect to the STI and STO connector located under the hood. PCM calibrations for 1995 utilize the NGS tool (New Generation Star Tester) which has an under dash connection and is capable of commanding diagnostic tests and monitoring PID’s on the diagnostic data link. Trucks built in 1995 do not have the under hood connector for the STAR II tester. Trucks built in 1994 have the connector under the dash for the NGS tool. The connector is not functional for diagnostics unless the PCM has been reflashed to a 1995 calibration. If a 1994 vehicle has been reflashed to a 1995 calibration, the STI and STO connector under the hood will not function with the STAR II tester.

Vehicle Serial Number:  The tenth position of the vehicle serial number (VIN) indicates model year.

  1. R=1994
  2. S=1995
  3. T=1996
  4. V=1997

Engine Serial Number:  The engine serial number is located on the calibration tag applied to the reservoir and also is stamped on the cylinder block on a pad located near the rear of the oil cooler.

Odometer:  Required for warranty purposes.

Chassis Style:  Helpful for evaluation of performance or fuel consumption complaints.

Vehicle GVW:  Helpful for evaluation of performance or fuel consumption complaints.

Transmission:  Helpful for evaluation of performance or fuel consumption complaints. Different PCM calibrations are required for manual and automatic transmissions.

Ambient Temperature:  Glow plug on time and exhaust back pressure operation are dependent on ambient temperature.

Customer Complaints:  Detailed description of customers concerns including conditions required to make the problem occur.

The left side of the form provides the technician with the procedures to diagnose a Hard Start/No Start complaint. Each test should be completed and the test values entered into each box.

The right side of the form provides the technician with the procedures to diagnose a performance complaint (examples listed below).

  • Low Power
  • Misfire/Rough Running
  • Stalling
  • Surging Smoke

Sufficient Clean Fuel

1. Sufficient Clean Fuel
  • Check fuel tank(s), drain sample from fuel filter while cranking engine.
  • Note if operator has indicated that the Water In Fuel or Fuel Restriction lamp has been illuminated.

CLEAN FUEL CHECK
Method Check
Visual  
Purpose

The purpose of this is to verify if the fuel system is receiving sufficient clean fuel to operate correctly.

Test Procedure

Route a hose from the fuel drain tube (to a clear container and open the drain. Crank the engine and observe the fuel flowing into the container. Stop cranking the engine when the container is half full.

NOTE: If, when attempting to drain the fuel filter, no flow occurs by opening the valve, the lid should be loosened one (1) turn. Loosening the lid will allow air to enter the top of the filter and fuel/water to drain from the bottom. This should only be done with the engine not running.

Observe the WATER IN FUEL light while cranking the engine. If the light is illuminated, the fuel may be contaminated with water.

Fuel flow out of the drain tube should be a steady stream. Insufficient flow could indicate fuel supply or fuel system problems.

Inspect fuel in container. The fuel should be clear or straw colored, but not cloudy and should be free of water and contaminates. Check fuel odor for presence of other fuels, such as gasoline.

Sufficient Clean Fuel

If engine oil is present in the fuel, it may indicate an injector “O” ring leak and subsequent loss of rail pressure. If that is suspected, check rail pressure during engine cranking (Test 11A).

Some sediment and water may be present in the fuel sample if the fuel filter has not been service for a prolonged period of time and/or if the sediment and water have not been drained recently. If that is the case, a second sample may be required to determine fuel quality.

Possible Causes (Low Or No Fuel Flow)
  • No fuel in tank.
  • If equipped with a fuel inline valve, it could be shut off. If the vehicle is equipped with dual fuel tanks the fuel transfer valve could be faulty.
  • Fuel supply line from tank(s) could be broken or crimped.
  • Fuel could be jelled (most likely in cold weather with #2 fuel) or the pickup tube screen in tank could be clogged.

Cloudy fuel indicated that the fuel may not be a suitable grade for cold temperatures, excessive water or contaminates may indicate that the tank and fuel system may need to be flushed and cleaned.

Tools Required
  1. Clear container approximately 1 quart.

Check Engine Oil Level

2. Check Engine Oil Level
  • Check for contaminants (fuel, coolant)
  • Correct grade/Viscosity

ENGINE OIL LEVEL CHECK
Method Check
Visual  
Purpose

To determine if there if enough oil or oil of sufficient quality to operate the injectors.

Test Procedure
Check oil level with oil gauge when vehicle is on level ground. If there is no oil or very little oil in the crankcase, the injectors will not operate.

If the oil level exceeds the recommended amount, it is possible the engine was incorrectly serviced or fuel is diluting the oil and filling the crankcase. Usually if a substantial amount if fuel is in the oil, the oil will have a fuel odor.

Inspect oil for color. A milky white oil indicates possible coolant contamination and will have an ethylene glycol odor.

Check service records for correct oil type and viscosity for the vehicle operating temperature. Single grade or 15W 40 oil is not recommended for cold ambient temperatures. Oil that has had extended drain intervals will have increased viscosity (become thicker) and will make engine cranking more difficult and starting less reliable at temperatures below freezing. Refer to the lube oil chart below to select the correct (viscosity) oil to use for the temperature condition(s) the engine will be operating in. Use CG-4/SH rated oil.

Lube Oil

The level in the oil reservoir should also be checked. Remove the inspection plug in top of reservoir (and check to see if the oil level in the reservoir is within one inch from the inspection plug.

Check Oil Level In Reservoir
Possible Causes
  • Oil level low – Oil leak, oil consumption, incorrect servicing.
  • Oil level high – Incorrect servicing, fuel dilution from lift pump, fuel dilution from injector “O” rings.
  • Oil contamination with coolant – Oil cooler, head gasket, porosity.
  • Low reservoir level – Insufficient oil pressure or pickup tube air leak.
Tools Required
  1. 1/4 inch drive ratchet or breaker bar to remove inspection plug.

Intake Restriction

3. Intake Restriction
  • Check filter minder if equipped.
  • or measure at WOT w/magnehelic gauge

INTAKE RESTRICTION CHECK
Instrument Check
Magnehelic/Filter Minder  
Purpose

This is a visual inspection to determine if the intake restriction is contributing to a low power condition. If the engine does have high inlet restriction, a considerable amount of black or blue smoke may be produced.

Test Procedure

Inspect the air cleaner inlet and ducting to assure that it is mot blocked or collapsed. Inspect air cleaner housing and filter for proper installation. Check filter minder for high restriction reading (If necessary, connect magnehelic gauge on the port at the air cleaner to measure intake restriction at high idle.

Measuring Intake Restriction
Possible Causes
  • Snow, plastic bags or other foreign material may block the air cleaner inlet.
  • Misrouted air cleaner ducting may collapse when the hood is shut.
  • On engines recently repaired, rags or cap plugs may have been inadvertently left in an intake pipe.
Tools Required
  1. Magnehelic Gauge

Perform KOEO On Demand Self Test

 4. Perform KOEO Test
  • Diagnostic Trouble Codes set during this test are current faults

Pass Code = P1111 

Diagnostic Trouble Codes _____

Purpose

To determine if the PCM has detected any fault conditions that may cause a performance problem.

Test Procedure

Connect the NGS tool to the diagnostic connector under the dash. Turn off all accessories. Turn the ignition key “ON”.

  • Perform the necessary vehicle preparation and visual inspection.
  • Select Vehicle and Engine Selection menu.
  • Select year, engine, and model.
  • Select DIAGNOSTIC DATA LINK.
  • Select PCM – POWERTRAIN CONTROL MODULE.
  • Select DIAGNOSTIC TEST MODES.
  • Select KOEO On Demand Self Test.
  • Follow operating instructions from menu.
  • Record DTCs and follow appropriate pinpoint test.

If any fault codes other than the PASS code sequence of P1111 is transmitted or if no codes are transmitted, refer to Diagnostic Trouble Code Description Chart in Scan Diagnostic Test section for appropriate pinpoint test.

NOTE: All current faults must be fixed before proceeding.
NOTE: IDM faults transmitted during this test are not current faults and have been set previously. IDM faults can only be cleared through the “retrieve continuous fault” menu through the C-ALL command. (IDM detected faults will not be displayed when retrieving continuous fault codes.)
New Generation Star Hookup With Adapter Cable Assembly
Possible Causes

The most likely PCM or IDM detectable faults that will cause a performance problem are:

  • MAP sensor faults.
  • Injector faults.
  • AP sensor faults.
  • CMP sensor faults.
  • Exhaust back pressure system faults.
  • Transmission control faults.
  • ICP system faults.
  • IDM faults.
Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500.

Retrieve/Clear Continuous DTCs

5. Retrieve Continuous Trouble Codes
 Select Continuous Trouble Code Retrieval from NGS test menu.
  • Diagnostic Trouble Codes retrieved during this test are historical faults.

Pass Code = P1111 

Diagnostic Trouble Codes _____

Purpose

To determine if the PCM has detected any historical or intermittent fault conditions that may cause a performance symptom. The condition that caused a continuous code may no longer exist.

Test Procedure
  • Turn the ignition key “ON.”
  • Select RETRIEVE/CLEAR CONTINUOUS DTCs.
  • Follow operating instructions from the menu.
  • Record DTCs and follow appropriate pinpoint test.
  • Continuous DTCs must be cleared after repair is made.
Tools Required
  1. NGS Scan Tool.

NOTE: Special instructions required to clear IDM Trouble Codes (1995 M.Y. only)

  • Ignition key “ON.”
  • Record IDM trouble codes stored in “KOEO ON DEMAND SELF TEST” mode.
  • Access “RETRIEVE/CLEAR CONTINUOUS DTCs” from NGS menu to clear IDM trouble codes from memory. IDM detected faults will not be displayed during this test, but can only be cleared from this menu.
  • Push “C-ALL” button on NGS tool.
  • IDM trouble codes are now cleared from memory.

KOEO Injector Electrical Self Test (Buzz Test)

NOTE: If unable to perform KOEO injector buzz test, disconnect IDM connector and check injector high and low side for short to ground condition or open circuits.
6. KOEO Injector Electrical Self Test
  • Select Injector Electrical Self-Test from the NGS test menu.
  • All injectors will momentarily buzz, then individual injectors will buzz in sequence 1 through 8.
  • Diagnostic Trouble Codes will be transmitted after test is completed.

Pass Code = P1111 

Injector Trouble Codes _____

Purpose

To determine if the injector solenoids and poppet valves are operating properly by buzzing all injectors together and then each injector in numerical sequence (1 through 8).

Test Procedure

Connect NGS scan tool to diagnostic connector under the dash. Select injector electrical self test from the NGS menu screen and follow the operating instructions on the screen.

NOTE: IDM Diagnostic Trouble Codes Will Display In The KOEO ON DEMAND SELF TEST MODE. (Accessing KOEO TEST MODE Is Required To Retrieve Fault Codes.) See Special Instructions For Clearing IDM Trouble Codes. The Instructions Are Listed With The KOEO On Demand Self Test Instructions.
Possible Causes
  • Open injector wire.
  • Bad injector connector.
  • Shorted wire or connector.
  • Open injector solenoid.
  • Defective IDM.
Tools Required

Rotunda New Generation Star (NGS) Scan Tool 007-00500 or equivalent.

7.3L DI Cylinder/Injector
New Generation Star Hookup With Adapter Cable Assembly

Tandem Fuel Pump Pressure

7A. Tandem Fuel Pump Pressure
  • Measure at regulator block.
  • Measure at WOT (high idle)/full load.

HIGH IDLE (3500 RPM) – FRONT TANK
Instrument Spec. Measurement
0-160 PSI Gauge 30-70 PSI (See Note)  

HIGH IDLE (3500 RPM) – REAR TANK
Instrument Spec. Measurement
0-160 PSI Gauge 30-70 PSI (See Note)  

If failed Test 7A, change filter and retest.

If pressure still low, proceed with step 7B.

NOTE: Tandem fuel pump pressure on MY96 and newer California F-series (“prime” injector) and all MY97 E-series engines should be 70-90 (steady) psi at idle.

Low fuel pressure at idle on these engines will cause the engine to have a noise described as “crackle” that will sound like an intermittent rod bearing knock.

Purpose

To determine if there is sufficient fuel pressure for correct engine operation.

Test Procedure

Note if operator has indicated that the High Fuel Restriction lamp has been illuminated. A restricted fuel filter may be causing low fuel pressure.

Connect line for 160 psi gauge to the Schrader adapter mounted on the fuel filter regulator block on side if the fuel filter housing. Run the engine at low idle and check for leaks in the line to the gauge. Operate the engine at high idle (maximum engine speed in park or neutral with the brakes set and the wheels blocked). Measure maximum fuel pressure and compare to specification.

Repeat for front and rear tanks.

Replace the fuel filter if the pressure is low and retest. If the fuel pressure is still low, go to Test 7B and check restriction from the fuel tank.

Measuring Tandem Pump Pressure
Possible Causes
    • A fuel filter may cause high restriction and low fuel pressure due to dirt of fuel jelling in cold ambient temperatures. Replace fuel filter and retest.
      NOTE: It may take more than one crank cycle to purge the air out of the fuel system.
    • Debris in the fuel regulator valve will cause low fuel pressure. Disassemble, inspect and clean.
Fuel Regulator Valve (Disassembled View)
  • A kinked or severely bent fuel line or blockage at the pickup tube could cause restriction and therefore low fuel pressure.
  • A loose fuel line in the suction side if the fuel system could cause air to be ingested into the system and cause low fuel pressure.
  • The fuel pump could have internal damage, e.g. ruptured diaphragm, seized plunger or leaking check valves.
Tools Required
  1. 0 to 160 PSI fuel pressure gauge, appropriate line with 1/8″ NPT fitting or Rotunda schrader adapter 014-00931-3.

Tandem Pump Inlet Restriction

7B. Tandem Pump Inlet Restriction
  • Measure at fuel inlet line.
  • Measure at WOT (high idle).
    TANDEM PUMP INLET RESTRICTION CHECK
    Instrument Spec. Check
    0-30″ (Hg) Vacuum Gauge 6 in. Hg. Max.  
  • If restriction is high, check for blockage between pump and fuel tank.
  • If restriction is okay, check regulator valve for sticking or internal debris.
Purpose

To determine if there is excessive restriction of fuel flow between the inlet fuel line to the fuel tank(s).

Test Procedure

Remove short hose at the fuel inlet line (left side of engine close to frame rail). The larger of the two fuel lines if the fuel inlet. The smaller line is fuel return to tank. Install tee fitting (014-00931-2) plumed to a 0 – 30″ (Hg.) vacuum gauge. Measure restriction at high idle (maximum engine speed out of gear with the brakes set and the wheels blocked). If restriction measured is above specification, this indicates a restriction exists between the engine and the fuel tank.

Measuring Tandem Pump Inlet Restriction
Possible Causes
  • Defective fuel tank transfer valve.
  • A kinked or severely bent fuel supply line.
  • Blockage at the pickup tube.
  • Very cold ambient temperatures may cause No. 2 diesel fuel (if used) to become jelled in the fuel lines.
Tools Required
  1. 0 to 30″ (Hg.) vacuum gauge and tee fitting to access fuel line (fabricated locally from common fittings).

Perform (KOER) On Demand Self Test

8. Perform KOER On Demand Test
  • Select KOER On Demand test from NGS test menu.

Pass Code = P1111 

KOER Diagnostic Trouble Codes _____

Purpose

To determine if the PCM has detected any fault conditions that would cause a performance problem while the engine is running. This will perform step tests on the injection control pressure system and the exhaust back pressure system.

Step tests are PCM controlled tests where the PCM commands a specific exhaust back pressure or injection control pressure and then measures the result. If a predetermined threshold is not reached a fault code will be generated. This test should be performed with the engine at normal operating temperature.

Test Procedure

Install the NGS scan tools and select KOER On Demand Self test from the NGS test menu. Follow directions on screen. Diagnostic trouble codes will be displayed at end of test.

Step Test Sequence:

  1. RPM increased to 850 RPM.
  2. ICP increased to 2465 PSI (17 MPA).
  3. ICP decreased to 725 PSI (5 MPA).
  4. RPM increased to 1250 RPM.
  5. EPR is activated to bring EBP to 22 PSI (150 KPAG).
  6. EPR then activated to bring EBP to PSI (30 KPAG).
  7. Engine returned to 650 RPM.
NOTE: Engine will operate at elevated low idle speed and run rough during this test.
Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500. (
New Generation Star Hookup With Adapter Cable Assembly

Cylinder Contribution Tests

9. Cylinder Contribution Tests
  • Performed after the KOER standard tests.
  • Assure that the engine is at operating temp. 158°F (70°C) minimum before performing test.
  • Select Cylinder Contribution test from the NGS test menu.
NOTE: The engine will run rough during test.

CCT Trouble Codes _____

NOTE: The EOT sensor must be at or above 170°F before the strategy in the PCM will allow the cylinder contribution test to be performed.
Purpose

To test individual power cylinders and injectors to determine if all are contributing equally to engine performance. Refer to (for cylinder locations.

This is a test performed after a standard KOER test is performed.

Test Procedure

Install the NGS scan tool and select KOER Cylinder Contribution Self test from NGS test menu.

NOTE: Engine will operate at an elevated low idle speed and run rough during this test.
NOTE: IDM diagnostic trouble codes can only be displayed in the KOEO on demand self test mode.
Possible Causes

Failing this test could indicate mechanical engine problems such as:

  • Broken compression rings.
  • Leaking or bent valves.
  • Bent push rods.
  • Bent connecting rods.
  • Faulty injector assembly.
  • Broken rocker arm bolts.

Refer to shop manual for base engine checks.

If the base engine condition meets specifications, the injector(s) may not be functioning correctly and will require replacement. The solenoid and wiring should have been checked in earlier tests. Verify KOEO Injector Electrical Self test passed.

Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500.
7.3L DI Cylinder/Injector
New Generation Star Hookup With Adapter Cable Assembly

Exhaust Restriction

10. Exhaust Restriction
  • Visually inspect exhaust system for damage.
  • Check if EBP device is closing at WOT.
  • Monitor EBP with the NGS tool with the engine temperature at 140°F minimum at WOT in park/neutral with parking brake applied.

EXHAUST RESTRICTION CHECK
Parameter Spec. Measurement
EBP 28 PSIA max. @ WOT  
Purpose

To determine if the exhaust system is sufficiently restricted to cause an engine performance problem.

Test Procedure

A thorough visual inspection should locate the problem quickly in most instances. Check tang position of EBP at high idle.

Use NGS tool and monitor PID “EBP.”

Checking Tang Position Of Exhaust Back Pressure (Butterfly) Valve At High Idle
Alternate Procedure

If a measurement is necessary, measure voltage at EBP using DVOM and an electrical breakout tee (D94T-50-A). Measure this pressure at high idle (maximum engine speed in park or neutral with the brakes set and the wheels blocked). It should not be greater than 2 volts.

Measuring Exhaust Back Pressure (Voltage)
Possible Causes
  • Collapsed tail pipe.
  • Clogged tail pipe.
  • Closed Exhaust Back Pressure device.
  • Clogged catalytic converter.
  • Damaged muffler.
Tools Required
  1. DVOM and Tee D94T-50-A or Rotunda New Generation Star (NGS) Scan Tool 007-00500.
New Generation Star Hookup With Adapter Cable Assembly

Air In Fuel System

11. Air In Fuel System
  • Remove fuel return line from fuel filter.
  • Install clear line from fuel filter to fuel return line.
  • View clear line during low idle for air.

AIR IN FUEL SYSTEM CHECK
Method Checks
Visual Front Tank, Rear Tank
Purpose

To determine if air being drawn into the fuel system.

Test Procedure
  • Remove the hose and clamps from return line at the fuel filter.
  • Install clear line (from the return line to the fuel filter. Loop the excess line at a point higher than the filter.
  • Observe the fuel in the clear line while the engine is running. The fuel should be flowing from the fuel filter to the return line to the tank. Once stabilized, only slight traces of air should be observed in the clear line.
  • If the fuel is foamy, check fuel supply lines from the tank to the lift pump for an air leak.
  • If there is no flow, remove the fuel strainer and clean return screen. Remove the fuel pressure regulator and clean the screen between the regulator and the fuel filter housing.
NOTE: If the filter has just been replaced, air may be present in the clear line until vented.
Air In Fuel System Test
Possible Causes

Loose or leaking fuel line fittings at:

  • Fuel tank(s).
  • Fuel tank transfer valve.
  • Connection between the transfer valve and engine.
  • “O” ring connection from chassis line to engine fuel inlet tube.
  • Clogged fuel return or filter de-aeration screens.
  • Hose clamps, rubber line on fuel pump.
Tools Required
  1. Clear line and hose clamps.

Injection Control Pressure Tests (Oil Aeration – Poor Idle Quality)

12A. Injection Control Pressure Tests (Oil Aeration – Poor Idle Quality)
  • Monitor ICP and RPM with the NGS tool.
  • Hold engine speed at WOT (wide open throttle) for 3 minutes.
    INJECTION CONTROL PRESSURE TESTS
    Parameter Spec. Measurement
    ICP 50 to 1250 PSI @ WOT  
  • If ICP signal increases above 1250 PSI after 3 minutes, anti-foam additives may have become depleted from oil. Change oil, retest.
Purpose

To determine if engine lube oil is being aerated and causing poor idle quality.

Test Procedure
NOTE: This test should be performed with engine at normal operating temperature.

Install the NGS scan tool. Access ICP PID on scan tool and monitor ICP pressure. Operate the engine at wide open throttle for 3 minutes.

Possible Causes
  • Extended oil drain intervals. The anti-foam additives in the oil may be depleted either from severe use or extended intervals.
  • Recent major engine repair/sealant impact on anti-foam.
  • Wrong type or grade of oil.
  • Excessive crankcase pressure.
  • Air leak oil pickup tube assembly.
Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500.
New Generation Star Hookup With Adapter Cable Assembly

Low Idle Stability (ICP Pressure)

12B. Low Idle Stability (ICP Pressure)
  • Check at low idle.
  • Monitor ICP and RPM with the NGS tool.

LOW IDLE STABILITY CHECK
Parameter Spec. @ 650 RPM Measurement
ICP 400 to 600 PSI Calif. And all Econoline  
ICP 550 to 700 PSI 49 State F-Series  

If engine RPM is unstable, disconnect the ICP sensor.

  • If idle speed is still unstable, replace IPR and retest.
  • If low idle smooths out, ICP signal faulty. (See ICP circuit diagnostics)
Purpose

To determine if idle stability and or low power is caused by a defective IPR valve or biased ICP signal.

Test Procedure
NOTE: This test should be performed with engine at normal operating temperature.

Install NGS scan tool. Access ICP PID on scan tool and monitor ICP pressure. Operate the engine at low idle. If engine does not stabilize, disconnect the ICP sensor. If low idle speed stabilizes with the ICP sensor disconnected, the problem is most likely in the ICP sensor circuit. Refer to Pinpoint X. If RPM does not stabilize, change the IPR valve and retest.

Possible Causes
  • Debris stuck in the IPR valve.
  • In-range ICP sensor or circuit failure.
Tools Required
  1. Rotunda New Generation Star (NGS) Scan Tool 007-00500. (
New Generation Star Hookup With Adapter Cable Assembly

Crankcase Pressure

13. Crankcase Pressure
  • Measure at oil fill with adapter and orifice tool P/N 5631 and 014-00743 installed.
  • Measure at WOT (high idle) no load RPM.

CRANKCASE PRESSURE CHECK
Instrument Spec. Measurement
Magnehelic 0 to 60″ h3O less than 6″ h3O  
Purpose

This test will measure crankcase pressure. Crankcase pressure is a measure of how well the power cylinders are sealed.

Test Procedure
NOTE: This test should be performed with engine at normal operating temperature. A cold engine will give higher readings.

Remove the ducting to the turbocharger inlet pipe and remove the inlet pipe and elbow that connects to the breather box. Block the outlet at the breather box. Install a protective screen over the turbocharger inlet.

Screw the crankcase breather tool and adapter in the oil fill cap hole. Plumb to the magnehelic gauge in the gauge block. Make sure the magnehelic gauge has been zeroed.

Start the engine and operate at WOT. Hold for 30 seconds minimum and take a stabilized reading.

NOTE: Orifice in restrictor tool must be unobstructed.
Crankcase Pressure Issue
Possible Causes
  • Broken or worn compression rings.
  • Polished or scored bores.
  • Leaking or bent valves.

Inspect air induction system. If the air induction system allows dirt to enter the power cylinder, it will quickly “dust” the engine causing high crankcase pressure.

Tools Required
  1. Magnehelic gauge, orifice restriction tool, oil fill adapter, protective screen.

Boost Pressure Test

14. Boost Pressure
  • Monitor MGP (manifold gauge pressure) and RPM with the NGS tool.
  • Road Test – Select appropriate gear to obtain desired engine speed at full load throttle position.

BOOST PRESSURE TEST
Parameter Spec. Measurement
MGP Manifold Gauge press. 15 PSIG Minimum @ 3000 RPM  
Purpose

To determine if the engine can develop sufficient boost to obtain rated power.

Test Procedure
NOTE: If the engine can obtain specified boost there is no engine power problem. There may be chassis or applications concerns, but the engine is performing as specified.

Install a “T” (manufactured locally out of common fittings) into the MAP (Manifold Absolute Pressure) sensor line the comes from the intake manifold.

NOTE: Make sure map sensor is hooked up for this test.

Connect a “T” to a 0 to 30 PSI gauge that is temporarily installed in the cab. Route the hose so it is not crimped and does not come in contact with any hot surface.

After the engine is up to operating temperature, find an open section of road and select 3rd gear. With the accelerator at WOT, note the boost reading at 3000 RPM. This test is best accomplished either climbing a hill or with the truck fully loaded.

Boost (Intake Manifold) Pressure Issue
Possible Causes
  • Restricted intake or exhaust.
  • Low fuel pressure.
  • Low injection control pressure.
  • Control system faults.
  • MAP hose disconnected.
  • Defective MAP sensor or incorrect MAP sensor for engine application being serviced.
  • Defective injector(s).
  • Defective turbocharger.
  • Base engine failure.
Tools Required
  1. “T” fitting and 0 to 30 (PSI) gauge.

ELECTRONIC CONTROL SYSTEM DIAGNOSTICS

Sensor And Actuator Diagnostic Procedures

Inspection

The basic diagnostic procedure recommended for most sensor and actuator circuits is to disconnect the harness at the connector and inspect for corrosion, bent pins, spread pins or any condition that could cause a loose or intermittent connection.

Remove Connector For Inspection
Measure Resistance to Ground
Connector Checks To Ground (B-)

The second step is to measure the resistance of all wiring harness connectors to ground (preferably the negative battery cable) to determine if a short to ground condition is present. It is important that during this test all accessories including the dome light be turned off, current flow in the system will affect resistance readings. If the reading is fluctuating greatly, disconnect the battery and measure to the negative battery cable.

  • Signal ground (marked “A” on all engine sensor harness connectors) should measure less than 5 ohms. (Signal ground in vehicle sensor connectors vary.)
  • The VRef and signal lines, with the processor connected, will normally measure greater than 1000 ohms.
    NOTE: C92, C97, and C98 indicate level of CMP. This is stamped into the case.

    NOTE: The symbols < & > are used in each diagnostic circuit page. They are defined as follows.

    • (<) INDICATES A VALUE LESS THAN
    • (>) INDICATES A VALUE GREATER THAN
    • EXAMPLE: < 5 OHMS = LESS THAN 5 OHMS
    • EXAMPLE: > 5 OHMS = MORE THAN 5 OHMS
  • Power ground on an actuator circuit should measure less than 5 ohms. The control side of an actuator circuit will normally measure greater than 1000 ohms.
Connector Voltage Checks

Turn the ignition key to the “ON” position and measure if the expected voltages are present at the connector. On circuits with expected voltages, this test will verify the integrity of that circuit. On circuits without an expected voltage, this test will determine if that circuit is shorted or miswired to a voltage source.

    • Signal return (marked “A” on all engine harness connectors) should measure less than .25 volts.
    • VRef should measure 5.00 volts +/-.50 volts. If this is higher or lower than expected, disconnect sensors one at a time to determine if a sensor is biasing the circuit and refer to VRef procedures.
Measuring VRef Voltage
  • Sensor signal lines will measure 0 to .25 volts if the circuit is designed to “pull down” when disconnected, or a higher voltage (normally 4.6 to 5, or 12 volts) if it is designed as a “pull up circuit.” A “pull up” signal circuit that measure the expected value normally indicates a good circuit.
  • Actuator circuits may be either on/off type circuits (normally 12 volts) or pulse width modulated circuits (12 volts controlled by a % duty cycle.)
  • Communication circuits between the Powertrain Control Module (PCM) and the Injector Driver Module (IDM) are designed to either “pull up” or “pull down.” That means that one end of the communication circuit is normally at a high or 12 volt level and the signal is created by the low side toggling or switching the high side to ground. Communication lines are best diagnosed with the breakout box installed and measuring the expected voltage with the key in the “ON” position and the engine off.
Harness Resistance Tests

Harness resistance tests are performed when a circuit is suspected of having high resistance or being open. These tests are performed with the breakout box connected and by measuring resistance from the sensor connector end to the processor connector. If an open circuit or high resistance is encountered, the problem is most easily isolated by separating the circuit at the interim connectors (normally the 42-pin connector below the power box) and measuring resistance through both halves of the circuit.

Operational Signal Checks

These checks are made with the breakout box installed and are normally measuring a signal voltage or frequency. They are useful for determining an in-range type fault or an intermittent connection.

In the case of an intermittent fault, monitoring a suspected circuit and recreating the environmental or physical conditions that caused the complaint will help verify if a problem is in a particular circuit.

It is critical when measuring the signal level of a circuit to understand its function and whether it is an analog voltage, digital frequency, sine wave or digital communication signal. A standard Digital Volt Ohm Meter (DVOM) has certain limitations in measuring any circuit that has a frequency.

Sensor And Actuator Locations On Engine

Sensor And Actuator Locations On Engine

Sensor Locations In Cab

Sensor Locations – Cab

AP/IVS Pedal Position Sensor/Idle Validation Switch

AP/IVS Pedal Position Sensor/Idle Validation Switch
Signal Functions

The Accelerator Pedal Position Sensor (AP) is a potentiometer type sensor which, when supplied with a 5 volt reference signal from the Powertrain Control Module (PCM), provides a linear analog voltage signal that indicates the driver’s demand for power.

The Idle Validation Switch (IVS) is a 0/12 volt switch that provides the PCM with a redundant signal to verify when the pedal is in the idle position.

The AP signal is used in calculating desired fuel quantity and injector timing.

Accelerator pedal position is one of the controlling variables in the calculation of desired injection control pressure.

Fault Detection/Management

Any detected malfunction of the AP or IVS sensor circuit will illuminate the CHECK ENGINE lamp.

An AP signal that is detected out of range high or low by the PCM will cause the engine to ignore the AP signal and will only allow the engine to operate at low idle only.

If a disagreement in the state if IVS and AP if detected by the PCM and the PCM can not discern if it is an AP or IVS fault or if it is and AP fault, the engine will be allowed to operate at low idle only.

AP/IVS Pedal Position Sensor/Idle Validation Switch Fault Detection/Management

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec. Comments
1 to Grd. < 5 ohms Resistance to Grd. (B-) check w/key off, > than 5 ohms harness is open. -AP sig. Grd.
2 to Grd. >1000 ohms Resistance less than 1000 ohms indicates a short to ground. -AP signal
3 to Grd. >1000 ohms Resistance less than 1000 ohms indicates a short to ground. -AP VRef
A to Grd. >1000 ohms Resistance less than 1000 ohms indicates a short to ground. -IVS signal

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON)
Test Points Spec. Comments
1 to Grd. 0 – .25 volts Signal ground no voltage expected.
2 to Grd. 0 – .25 volts If greater than .25 volts signal circuit is shorted to Vref or battery. -AP signal
3 to Grd. 5 +/- .5 volts VRef check key on, if VRef not present check open/short to Grd #91 to B, see VRef circuit.
A to Grd. 0 – .25 volts If greater than .25 volts signal circuit ground wire is shorted to Vref or battery.
B to Grd. 12 +/- 1.5 volts <10.5v check for poor connection, 0 v check for open/short to Grd circuit or blown fuse.

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec. Comments
#91 to 1 < 5 ohms Resistance from 104 pin connector to harness connector – Signal Ground
#89 to 2 < 5 ohms Resistance from 104 pin connector to harness connector – AP Signal
#90 to 3 < 5 ohms Resistance from 104 pin connector to harness connector – VRef
#5 to A < 5 ohms Resistance from 104 pin connector to harness connector – IVS Signal
V IGN. to B < 5 ohms Resistance from V IGN, power to harness connector

OPERATIONAL VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED KEY “ON”)
Position AP Test Points (+) #89 to (-) #91 IVS Test Points (+) #5 to (-) #91 Comments
Voltage Voltage
Low Idle .37 to 1.4 V <.25 volts Minimum IVS transition point .2 volts above base idle voltage.
High Idle 3 to 4.5 V 12+/- 1.5 volts Maximum IVS transition point @ 1.6v of AP signal

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
0122 AP signal was less than 0.37 volts for more than 0.5 seconds *
0123 AP signal was greater than 4.56 volts for more than 0.5 seconds *
0221 AP and IVS disagree
0220 PCM did not receive IVS transition
* IF FAULT CODE IS SET, ENGINE OPERATION WILL DEFAULT TO RUN AT LOW IDLE SPEED ONLY.

Barometric Pressure (BARO) Sensor

Barometric Pressure (BARO) Sensor
Signal Functions

The BARO (Barometric Pressure) sensor is a variable capacitance sensor that when supplied with a 5 volt reference signal from the PCM produces a linear analog voltage signal that indicates barometric pressure.

The BARO signal if used to determine altitude to adjust timing and fuel quantity to optimize engine operation and control smoke throughout all altitude conditions.

The BARO signal is one of the variables used to calculate glow plug “ON” time. At higher altitudes, glow plug “ON” time is increased to insure faster clean up of startup smoke.

Fault Detection/Management

A BARO signal that is detected out of range high or low by the PCM will cause the PCM to ignore the BARO signal and use the Manifold Absolute Pressure (MAP) signal sensed at low idle as an indication of barometric pressure. If the MAP signal has also failed, a fixed value of 29.61 In. Hg. (14.6 PSI) is used as the default. The NGS tool will display the PID default value of 29.61 In. Hg. (14.6 PSI) when the BARO system has failed.

Barometric Pressure (BARO) Sensor Fault Detection/Management
NOTE: After removing connectors always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
(1) to Grd. < 5 ohms Resistance to chassis Grd, check w/key off, > than 5 ohms the harness is open.
(2) to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground.
(3) to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground.

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON)
Test Points Spec. Comments
(1) to Grd. 0 – .25 volts If greater than .25 volts signal wire is shorted to VRef or battery.
(2) to Grd. 5 Volts +/- .5 VRef check with key ON, if voltage is not spec., see VRef circuit.
(3) to Grd. 0 – .25 volts If greater than .25 volts signal wire is shorted to VRef or battery.

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
#91 to (1) < 5 ohms Resistance from sensor connector to 104 pin connector – Signal Ground
#90 to (2) < 5 ohms Resistance from sensor connector to 104 pin connector – VRef
#84 to (3) < 5 ohms Resistance from sensor connector to 104 pin connector – BARO signal

OPERATIONAL VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) #84 to (-) #91 kPa Comments
Voltage In. Hg.
4.89 31.0905 105 High atmospheric pressure
4.6 29.61 100 Normal atmospheric pressure at sea level
2.6 60 Normal atmospheric pressure at 10,000 feet

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
0108 Signal voltage was greater than 4.9 volts for more than .2 seconds
0107 Signal voltage was less than .04 volts for more than .2 seconds

Camshaft Position (CMP) Sensor

Camshaft Position (CMP) Sensor
Signal Functions

The CMP (Camshaft Position) sensor is a Hall Effect type sensor that generates a digital frequency as windows on the timing disk pass through its magnetic field. The frequency of the windows passing by the sensor as well as the width of selected windows allows the PCM to detect engine speed and position.

Is determined by counting 24 windows on the timing sensor disk each camshaft revolution.

The position of cylinder #1 and #4 is determined by distinguishing a narrow or wide window in the camshaft timing sensor disk.

Allows the PCM to discern when the engine is in the off, crank or run mode.

Engine speed is one of the controlling variables in the calculation if desired injection control pressure.

Exhaust back pressure control is a function of the engine speed and load.

Engine torque and fuel is controlled and is dependent on engine speed. Fuel quantity is determined by engine speed.

Fault Detection/Management

An inactive CMP signal during cranking is detectable by the PCM. An inactive CMP signal will cause a no start condition. Electrical noise can also be detected by the PCM, if the level is sufficient to effect engine operation a corresponding fault code will be set. The engine will not operate without a functioning CMP signal. The NGS tool will display PID value of zero RPM and zero fuel-PW when no CMP signal is present.

Camshaft Position (CMP) Sensor Fault Detection/Management
NOTE: After removing connector always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
A to Grd. < 5 ohms Resistance to chassis Grd, check w/key off, if > than 5 ohms the harness is open.
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground.
C to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground.

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON)
Test Points Spec. Comments
A to Grd. 0 – .25 volts If greater than .25 volts signal wire is shorted to VRef or battery.
B to Grd. 5 Volts +/- .5 VRef check with key ON, VRef not present check open/short to Grd, see VRef circuit
C to Grd. 12 +/- 1.5 volts If < than 10.5 v check for poor connection, if 0 v check for open/short to Grd circuit

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
#65 to A < 5 ohms Resistance from harness connector to 104 pin connector – Signal Ground (CMP has dedicated Grd circuit)
#90 to B < 5 ohms Resistance from sensor connector to 104 pin connector – VRef
#49 to C < 5 ohms Resistance from harness connector to 104 pin connector – CMP signal

OPERATIONAL VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) #49 to (-) #65 Comments
Voltage Position
12+/- 1.5 v Vane With the breakout box installed, the CMP sensor & PCM connected, bar engine by hand
1.5+/-.5 v Window The CMP signal voltage should change voltage state as timing wheel on cam is rotated

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
0344 Incorrect number of sync to transition counts detected, possible intermittent CMP sensor/circuit fault
0341 Electrical noise detected, check wire routing and grounds
0340 Inactive CMP signal detected during engine cranking when ICP pressure was sufficient for starting

Exhaust Back Pressure (EBP) Sensor

Exhaust Back Pressure (EBP) Sensor
Signal Functions

The EBP (Exhaust Back Pressure) sensor is a variable capacitance sensor that when supplied with a 5 volt reference signal from the PCM produces a linear analog voltage signal that indicates exhaust back pressure.

The EBP sensor’s primary function is to measure exhaust back pressure so that the PCM can control the exhaust back pressure regulator when needed.

Fault Detection/Management

An EBP signal that is detected out of range high or low by the PCM will cause the engine to ignore the EBP signal and disable exhaust back pressure operation.

The NGS tool will display a fixed PID value of 43.5 PSI (300 kPa) for EBP when exhaust back pressure is in default.

Exhaust Back Pressure (EBP) Sensor Fault Detection/Management
NOTE: After removing connector always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
A to Grd. < 5 ohms Resistance to Grd check w/key off, if > than 5 ohms the harness is open – Signal Grd.
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground – VRef
C to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground – EBP signal

Connector Voltage Checks (Check with Sensor Connector Disconnected and Ignition Key On)
Test Points Spec. Comments
A to Grd. 0 – .25 volts If greater than .25 volts signal ground is open or shorted to VRef or battery.
B to Grd. 5 Volts +/- .5 VRef check with key “ON”, if voltage not in spec., see VRef circuit
C to Grd. 0 – .25 volts If greater than 0.25 volts, signal wire is shorted to VRef or battery

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
#91 to A < 5 ohms Resistance from sensor connector to 104 pin connector – Signal Ground
#90 to B < 5 ohms Resistance from sensor connector to 104 pin connector – VRef
#30 to C < 5 ohms Resistance from harness connector to 104 pin connector – EBP signal

OPERATIONAL SIGNAL CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) #30 to (-) #91 KPAG Comments
Voltage PSIG
.8 – 1.0 v 0 0 Signal with key “ON” and engine OFF (Value dependent upon atmospheric pressure and altitude.)
.8 – 1.0 v 0 0 Normal warm idle signal
1.19 v 14.8 10.0 Minimum signal expected at 2300 RPM with warm engine (See EPR diagnostics.)

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
0472 Signal voltage was less than .039 volts for more than 0.2 seconds
0473 Signal voltage was greater than 4.90 volts for more than 0.2 seconds

Engine Oil Temperature (EOT) Sensor

Engine Oil Temperature (EOT) Sensor
Signal Functions

The Engine Oil Temperature (EOT) sensor is a thermistor type sensor that has a variable resistance which changes when exposed to different temperatures. When interfaced with PCM it produces a 0 to 5 volt analog signal that will measure engine oil temperature.

The EOT signal is used to determine the timing and quantity of fuel required to optimize starting over all temperature conditions.

Fuel quantity and timing is controlled throughout the total operating range to compensate for oil viscosity changes due to temperature variations and insure that adequate torque and power is available.

At oil temperatures below 32°F (0°C), low idle is incrementally increased to a maximum of 1200 RPM at -20°F (-30°C).

At oil temperatures below 95°F (35°C), low idle is incrementally increased to a maximum of 1200 RPM at – 20°F (-30°C)

Fault Detection/Management

An EOT signal that is detected out of range high or low by the PCM will cause the PCM to ignore the EOT signal and default to a 212°F (100°C) value for engine oil temperature. The CHECK engine lamp will also be illuminated as long as the fault condition exists. The NGS tool will display a fixed PID value of 212°F (100°C) when EOT is in default.

Engine Oil Temperature (EOT) Sensor Fault Detection/Management
NOTE: After removing connector always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
A to Grd. < 5 ohms Resistance to chassis ground, check with key OFF, if > than 5 ohms the harness is open
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON)
Test Points Spec. Comments
B to Grd. 4.8 – 5.0 v Pull up voltage, if no or low voltage, circuit has open or high resistance or short to ground
A to Grd. 0 -.25 v If greater than .25 volts signal ground is open or shorted to VRef or battery.

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
#91 to A < 5 ohms Resistance from harness connector to 104 pin connector – Signal ground
#38 to B < 5 ohms Resistance from harness connector to 104 pin connector – EOT Signal

OPERATIONAL SIGNAL CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) #38 to (-) #91 Temp. °C Resistance Comments
Voltage Temp. °F
0.53 v 248 120 1.19 K ohms  
0.96 v 205 96 2 K ohms  
1.37 v 176 80 3.84 K ohms  
4.37 v 32 0 7.21 K ohms  
4.60 v -5 -20 8.22 K ohms  

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Circuit Faults
0197 Signal was less than .04 volts for more than 0.2 seconds
0198 Signal voltage was greater than 4.9 volts for more than 0.2 seconds.
0195 Engine oil temperature less than 158° F (70° C) during KOER test (Access denied.) or engine oil temperature greater than 242° F (117° C) during KOER test (aborts Test.)

Exhaust Back Pressure (EPR) Regulator

Exhaust Back Pressure (EPR) Regulator
Output Functions

Exhaust back pressure regulator is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. The PCM uses the measured exhaust back pressure, (ambient) intake air temperature, engine oil temperature and engine load to determine the desired exhaust back pressure. Valve position is controlled by switching the output signal circuit to 12 volts inside the PCM. On/off time is modulated from 0 to 99% dependent upon the exhaust back pressure desired.

Upon each initial engine start-up, the PCM exercises the exhaust back pressure valve by commanding it to cycle on and off once. If upon start-up the temperature of intake air sensed by the IAT sensor is < 37°F (5°C) and the oil temperature sensed by the EOT sensor is between 32°-140°F (0-60°C) it will continue to keep the back pressure valve partially closed. As the oil temperature rises during engine operation, the PCM will control the valve in response to the rising oil temperature.

Fault Detection/Management

An open or shorted to ground control circuit can be detected by an on demand output circuit check performed during the engine off test.

Problems with either the Exhaust Back Pressure Device or the tube between the exhaust manifold and the EBP sensor can be detected during the exhaust back pressure step test, in which the PCM commands and then measures a specific preprogrammed pressure and then measures time for pressure decay during the engine running test.

If the PCM detects and EBP, EOT or IAT sensor fault it will disable the exhaust back pressure regulator.

Exhaust Back Pressure (EPR) Regulator Fault Detection/Management
NOTE: After removing connector always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
A to Grd. < 5 ohms Resistance greater than 5 ohms indicates an open circuit or bad ground
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
Pwr. Grd. to Pin #42 2.5 to 20 ohms Resistance through EPR circuit including regulator, check with regulator connector connected (unnecessary to check next points if okay)
A to Grd. < 5 ohms Resistance from regulator connector to Pwr. Ground
B to #42 < 5 ohms Resistance from regulator connector to 104 pin connector

CIRCUIT FAULT CODE DESCRIPTIONS
Fault Code Description
0475 Output circuit check detected during Standard test, indicates high or low resistance in circuit

EXHAUST BACK PRESSURE SYSTEM FAULT CODE DESCRIPTIONS
Fault Code Description
0478 EPR pressure was greater than 71 in.Hg., (340 kpaG), (35 PSI) for 2.5 seconds.
0476 Indicates that EPR pressure of 22 in.Hg. (75 kPa) commanded during EBP engine running test was not obtained (Plugged line or exhaust back pressure device failure.)

Glow Plug Control

Glow Plug Control
Output Functions

Controls the current flow to the glow plugs. Glow plug relay “ON” time is controlled by the PCM and is a function of engine oil temperature, barometric pressure and battery voltage. “ON” time normally varies between 10 to 120 seconds. The glow plugs are self-limiting glow plugs and do not require cycling on and off. (The glow plug relay will only cycle on and off repeatedly when there is a system voltage condition greater than 14.5 volts.)

Lamp that indicates to the operator when the glow plugs have been on long enough to crank the engine. It is controlled by the PCM. Wait to Start lamp “ON” time is a function of engine oil temperature, barometric pressure and battery voltage. “ON” time normally varies between 1 to 10 seconds. (NOTE: Wait to Start lamp “ON” time is independent from glow plug relay on time.)

Fault Detection/Management

An open or shorted to ground glow plug relay in the control side (coil) or Wait to Start lamp circuit can be detected by an on demand output circuit check performed during the Engine Off Tests.

The glow plug relay (power/switch) side, glow plugs and glow plug harness problems can not be detected by the PCM.

Glow Plug Control Fault Detection/Management

GLOW PLUG RELAY OPERATION (VOLTAGE CHECKS)
Test Points Spec Comments
B+ terminal to ground B+ Relay switch power, B+ should be present at all times (terminal with single 6 gauge wire). Check connection at starter or fusible links if no power (voltage) present.
Glow Plug Feed to Grd. B+ Glow plug feed voltage should be present 10 to 120 seconds after key is cycled on, dependent upon battery voltage, barometric pressure (altitude) and engine oil temperature.
B to Ground B+ Relay coil power. Voltage should be present when ign. key is ON – Check fuse if no voltage.
Pin #101 to Ground 0v / 12v Glow plug control, switched to (Grd) by PCM during operation. 0v = relay ON, 12v = relay off.

Glow Plug and Harness Operation 

NOTE: Measure glow plug resistance to ground with the pigtail connector (014-00935) installed at the valve cover connector; then measure resistance from the glow plug feed stud to the harness connector.

Glow Plug and Harness Operation
Test Points Relay to Harness Connector Comments
Glow Plug No. Pigtail Connector to Ground (B-)
Spec <.1 to 2 ohms < 6 ohms

Relay to Harness Connector

NOTE: All engine harness connectors for glow plug/injectors should be disconnected before taking measurements.

High resistance could indicate an open circuit in the engine harness between the glow plug connector and the relay.
#1     Pigtail Connector to Ground B-High resistance could indicate an open circuit in the UVC (under the valve cover) harness or in the glow plug. Glow plug resistance should measure .1 to 2 ohms dependent upon engine temperature.
#3      
#5      
#7      
#2      
#4      
#6      
#8      

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
0380 OCC CHK performed by PCM during engine off test. Indicates high or low resistance in GP relay coil circuit.
0381 OCC CHK performed by PCM during engine off test. Indicates high or low resistance in GP lamp circuit.

Intake Air Temperature (IAT) Sensor

Intake Air Temperature (IAT) Sensor
Signal Functions

The Intake Air Temperature (IAT) sensor is a thermistor type sensor that has a variable resistance that changes when exposed to different temperatures. When interfaced with the PCM it produces a 0-5 volt analog signal that will deduce temperature.

The IAT sensor’s primary function is to measure intake air temperature in order to determine when the exhaust back pressure function is needed.

Fault Detection/Management

An IAT signal that is detected out of range high or low by the PCM will cause the engine to ignore the IAT signal, disable exhaust back pressure operation and assume an ambient temperature of 59°F (15°C).

The NGS tool will display a fixed PID value of 58°F (15°C) as ambient temperature when a IAT signal fault is present.

Intake Air Temperature (IAT) Sensor Fault Detection/Management
NOTE: After removing connector always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
A to Grd. < 5 ohms Resistance to chassis ground, check with key OFF, if > than 5 ohms the harness is open
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON
Test Points Spec Comments
B to Grd. 4.8 – 5.0 v Pull up voltage, if no or low voltage, circuit has open or high resistance or short to ground
A to Grd. 0 – .25 v If greater than .25 volts signal ground is open or shorted to VRef or battery.

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
#91 to A < 5 ohms Resistance from harness connector to 104 pin connector – Signal ground
#39 to B < 5 ohms Resistance from harness connector to 104 pin connector – IAT Signal

OPERATIONAL VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) #39 to (-) #91 Temp °C Resistance Comments
Voltage Temp °F
1.72 v 122 50 10.9 K ohms  
3.09 v 68 20 37.34 K ohms  
3.897 v 32 0 68.75 K ohms  
4.33 v 0 -18 120.9 K ohms  
4.537 v -40 -40 194.3 K ohms  

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Circuit Faults
0112 Signal was less than .04 volts for more than 0.2 seconds
0113 Signal voltage was greater than 4.9 volts for more than 0.2 seconds.

Injection Control Pressure (ICP) Sensor

Injection Control Pressure (ICP) Sensor
Signal Functions

The Injection Control Pressure (ICP) sensor is a variable capacitance sensor that when supplied with a 5 volt reference signal from the PCM produces a linear analog voltage signal that indicates pressure.

The ICP sensor’s primary function is to provide a feedback signal to indicate injection control pressure to enable the PCM to command the correct injector timing and pulse width and the correct injection control pressure for proper fuel delivery at all speed and load conditions.

Fault Detection/Management

If the PCM detects a malfunctioning ICP sensor, the CHECK ENGINE lamp will illuminate. The PCM will go to open loop control of injection control pressure. (Operate from an estimated ICP pressure.)

At idle, the NGS tool will display a fixed PID value of 725 PSI for ICP when a signal fault is present.

Injection Control Pressure (ICP) Sensor Fault Detection/Management
NOTE: After removing connector always check for damaged pins, corrosion, loose terminals etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec Comments
A to Grd. < 5 ohms Resistance to chassis ground, check with key OFF, if > than 5 ohms the harness is open
B to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground
C to Grd. > 1000 ohms Resistance less than 1000 ohms indicates a short to ground

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON)
Test Points Spec Comments
A to Grd. 0 – .25 v If greater than .25 volts signal wire is open or shorted to VRef or battery.
B to Grd. 5 volts +/- .5 VRef check with key “ON”, if voltage not in spec., see VRef circuit
C to Grd. 0 – .25 volts If greater than 0.25 volts, signal wire is shorted to VRef or battery

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec Comments
#91 to A < 5 ohms Resistance from sensor connector to 104 pin connector – Signal ground
#90 to B < 5 ohms Resistance from sensor connector to 104 pin connector – VRef
#87 to C < 5 ohms Resistance from sensor connector to 104 pin connector – ICP Signal

OPERATIONAL VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) #87 to (-) #91 MPA Comments
Voltage PSI
1.0 v 580 4 Minimum required at engine cranking speed 100 RPM
.88 – 1.19 v 540-790 3.7-5.5 Normal warm idle voltage signal
1.38 – 1.53 v 960-1088 6.6-7.5 Normal high idle voltage signal
3.22v 2520 17.4 Snap accel or full load pressure signal

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Circuit Faults
1280 Signal voltage was less than .039 volts for more than 0.2 seconds
1281 Signal voltage was greater than 4.90 volts for more than 0.2 seconds
1212 Signal above 1.625 volts with engine off (1160 psi, 8 MPa)

Injector Drive Circuit Operation

Injector Drive Circuit Operation
Signal Functions

The high side drive output function is to supply to the injectors a power supply of 115 volt DC at a maximum of 10 amps. This power supply is available to the injectors as required.

The low side drive outputs control the injector on time (fuel quantity), timing (in relation to TDC) and sequencing (firing order). The IDM controls (fires) each individual injector by completing the ground circuit to each injector solenoid. A valid Cylinder Identification (CI) and Fuel Demand Command Signal (FDCS) must be sent from the PCM to the IDM before an injector will be allowed to fire.

Fault Detection/Management

The Injector Driver Module (IDM) is capable of detecting, while the engine is running individual injector open and shorts to either ground or battery. It is also capable of detecting right or left bank high side opens or shorts to ground. A special On-Demand Buzz test will also allow the operator to enable all injector solenoids while the engine is off to verify circuit operation.

NOTE: IDM detected diagnostic fault codes will not be transmitted if the EF line is not functioning, however, the engine will function normally. The PCM will detect the communication error and set a fault code.
NOTE: If a short to ground condition is detected on an individual injector, (low side), the IDM will discontinue the power to the back with the shorted injector, enable the CHECK ENGINE lamp and operate the engine on four cylinders.
Injector Drive Circuit Fault Detection/Management
NOTE: After removing connectors always check for damaged pins, corrosion, loose terminals etc.
NOTE: Test all injector harness and valve cover connections at Test Points indicated.

ENGINE HARNESS CONNECTOR TO CHASSIS GROUND
Test Points Spec. Comments
B   Injector low side – short to ground or battery codes may be set if shorted to ground
C > 1000 ohms Injector power feed high side – codes 1291 or 1292 may be set if shorted to ground
D > 1000 ohms Injector low side – codes: 0261, 1264, 0267, 0270, 0273, 0276, 0279, 0282, may be shorted to ground

VALVE COVER GASKET CONNECTOR TO CHASSIS GROUND (CHECK WITH PIGTAIL CONNECTOR INSTALLED ON GASKET CONNECTOR)
Test Points Spec. Comments
B > 1000 ohms Injector low side – codes: 0261, 1264, 0267, 0270, 0273, 0276, 0279, 0282, may be shorted to ground
C > 1000 ohms Injector power feed high side – codes 1291 or 1292 may be set if shorted to ground
D > 1000 ohms Injector low side – codes: 0261, 1264, 0267, 0270, 0273, 0276, 0279, 0282, may be shorted to ground

UNDER VALVE COVER HARNESS AND INJECTOR SOLENOID RESISTANCE CHECKS (CHECK WITH PIGTAIL CONNECTOR INSTALLED ON GASKET CONNECTOR)
Test Points Spec. Comments
B to C 3.4 +/- 2 ohms Resistance through injector solenoid and UVC harness – codes 1271 – 1278 may be present if open, codes 1261 – 1268 may be present if injector or harness shorted together.
C to D 3.4 +/- 2 ohms  

ENGINE HARNESS TO IDM CONNECTOR CHECKS (MEASURE TO APPROPRIATE PIN)
Test Points Spec. Comments
B to IDM < 5 ohms Injector low side – codes(s) 1271 – 1278 present if open present
C to IDM < 5 ohms Injector power. feed high side – codes(s) 1293 – 1294 present if open, code 1297 indicates sides shorted together
D to IDM < 5 ohms Injector low side – codes(s) 1271 – 1278 present if open present

Injection Pressure Regulator (IPR)

Injection Pressure Regulator (IPR)
Output Functions

Is a variable position valve that controls injection control pressure. The PCM uses many input variables to determine the desired injection control pressure.

Battery voltage is supplies to the IPR when the ignition key is in the on position. Valve position is controlled by switching the output signal circuit to ground inside the Powertrain Control Module (PCM). On/off time is modulated from 0 to 50% dependent upon the desired injection control pressure.

Fault Detection/Management

An open or a short to ground control circuit can be detected by an on demand output circuit check performed during the engine off test.

The PCM is capable of detecting, while the engine is running, if desired injection control pressure is equal to measured injection control pressure. If the measured injection control pressure does not reasonably compare to the desired injection control pressure, the PCM ignores the measured ICP signal and attempts to control the engine with the desired value. (If the problem was in the sensor circuit, this strategy causes little performance deterioration, if the problem is in the control circuit, engine performance will probably still be unsatisfactory).

A faulty IPR or problem with the high pressure oil system can be detected by engine running test during the injection control pressure step test. During this test, the PCM commands and measures two specific pre-programmed pressures. A fault code is set, if the pressures can not be maintained.

NOTE: The engine will not operate with an IPR circuit that is not functioning.
Injection Pressure Regulator (IPR) Fault Detection/Management
NOTE: After removing connectors always check for damaged pins, corrosion, loose terminal etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH IPR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec. Comments
A to Grd. > 1000 ohms Resistance to chassis ground, if shorted to ground, #71 or #97
B to Grd. > 1000 ohms A short to ground will command full IPR pressure, code 1282 may be set

IPR VOLTAGE CHECK (CHECK WITH REGULATOR CONNECTOR DISCONNECTED)
Test Points Spec. Comments
A to Grd. B+ Battery voltage from #71 or #97 check with key “ON” (GP relay coil is supplied from PCM)
B to Grd. 0 -.25 v If greater than .25 volts, signal wire is shorted to VRef or battery

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec. Comments
#83 to #71 or #97 5 to 20 ohms Resistance through entire IPR circuit including regulator, check with regulator connector connected
#83 to B < 5 ohms Resistance from 104 pin connector to regulator connector
#71 or #91 to A < 5 ohms Resistance from power supply, #71 or #97 to regulator connector

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
1283 Output circuit detected during Standard test, indicates high or low resistance in circuit.
1282 ICP pressure was greater than 3675 PSI (25 MPa) or 1.5 seconds. (Possible grounded IPR control circuit.) (Refer to injection control pressure diagnostics if not electronic fault.)
1211 If set during normal engine operation indicates engine is operating in open loop control and ICP pressure is above or below desired pressure (Refer to ICP control system diagnostics.) or if set during engine running test, indicates ICP system failed step test and could not maintain commanded pressure.

Manifold Absolute Pressure (MAP) Sensor

Manifold Absolute Pressure (MAP) Sensor
Signal Functions

The Manifold Absolute Pressure (MAP) sensor is a variable capacitance sensor which operates on a 5 volt reference signal from the PCM to produce a digital frequency signal that indicates pressure.

The MAP signal is used to control smoke by limiting fuel quantity during acceleration until a specified boost pressure is obtained

Optimizes injection timing for boost pressure measured.

Fault Detection/Management

A MAP signal that is detected by the PCM to be out of range or at an incorrect value for specific conditions will cause the PCM to ignore the MAP signal and will operate the engine with the values from estimated MAP. (Operate from a calculated boost pressure signal)

The NGS tool will display a fixed PID value of 14.6 PSI (100 kPa) with a MAP signal fault present.

Manifold Absolute Pressure (MAP) Sensor Fault Detection/Management
NOTE: After removing connectors always check for damaged pins, corrosion, loose terminal etc.

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Test Points Spec. Comments
A to Grd < 5 ohms Resistance to chassis ground check w/key off, if > than 5 ohms the harness is open
B to Grd > 1000 ohms Resistance less than 1000 ohms indicates a short to ground – VRef
C to Grd > 1000 ohms Resistance less than 1000 ohms indicates a short to ground – MAP signal

CONNECTOR VOLTAGE CHECKS (CHECK WITH SENSOR CONNECTOR DISCONNECTED AND IGNITION KEY ON)
Test Points Spec. Comment
A to Grd. 0 – .25 volts If greater than .25 volts signal circuit is shorted to VRef or battery
B to Grd. 5 volts +/- .5 VRef check with key “ON”, if voltage not in spec., see VRef circuit
C to Grd. 4.8 – 5.0 volts Pull up voltage, if no or low voltage circuit has open or high resistance or short to ground

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON ENGINE HARNESS ONLY)
Test Points Spec. Comments
#91 to A < 5 ohms Resistance from sensor connector to 104 pin connector – Signal ground
#90 to B < 5 ohms Resistance from sensor connector to 104 pin connector – VRef
#34 to C < 5 ohms Resistance from sensor connector to 104 pin connector – MAP signal

OPERATIONAL VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED IN LINE WITH THE PCM)
Test Points (+) 34 to (-) #91 KPAG MGP (PSI) Comments
Frequency PSIA
111 Hz 14.7 101 0 (0) Freq with key on, engine off. atmospheric pressure dependent on altitude and BARO psi.
130 Hz 20 138 38 (5.3) Expected frequency values at absolute pressures.
167 Hz 30 207 107 (15.3)  
203 Hz. 40 276 176 (25.3)  

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Description
Circuit Faults:
0237 Signal frequency was greater than 256 Hz. for more than 0.1 seconds.
0235 Signal frequency was less than 78 Hz. or inactive for more than 0.10 seconds.
System Faults:
0236 Detected high boost signal at low idle. (Restricted MAP line.) (Inrange Fault).

PCM – IDM Communications

PCM – IDM Communications
Signal Functions

Cylinder Identification (CI) signal is a 0 to 12 volt wave form signal that communicates from the PCM to the IDM the position of cylinders 1 & 4. This signal is used by IDM to synchronize the injector firing sequence. This signal is calculated from the signal generated from the Camshaft Position Sensor (CMP). The CI signal is generated by the PCM by “pulling down” (switching to grd.) a 12 volt communication circuit in the IDM.

Fuel Demand Command signal is a 0 to 12 volt wave form signal that communicates from the PCM to the IDM the required engine timing and duration of injector firing. The timing and duration of the signal is determined by the PCM calibration and the signals of various sensor inputs. The FDCS signal is generated by the PCM by “pulling down” (switching to ground) a volt communication circuit in the IDM.

Injector Driver Module Feedback signal is a 0 to 12 volt wave form signal that communicates from the IDM to the PCM a mirror image of the FDCS signal. Extensions of the EF (Electronic Feedback) signal can indicate to the PCM possible problems with the injectors by the IDM as the engine is running. An EF toggle (83 hz. Signal) is generated when the key is first turned “ON” and before the engine starts, communicates to the PCM that the IDM is powered up. In an engine off or engine running diagnostic mode, the EF signal is also used to communicate diagnostic information from the IDM to the PCM. The EF signal is generated by the IDM by “pulling down” (switching to gnd) a 12 volt communications circuit in the PCM.

Fault Detection/Management

Intermittent open or short to ground conditions can be detected by the IDM through IDM stuck high or low codes (1218 & 1219). Active faults can be detected by an on demand output circuit check performed during engine off tests.

NOTE: The engine will not operate without a functioning CI circuit.

Active faults can be detected by an on demand output circuit check performed during engine off tests.

NOTE: The engine will not operate without a functioning FDCS circuit.

Active faults can be detected by a toggle sequence that the PCM looks for on start up. The WARN lamp will be illuminated if this is detected.

NOTE: IDM diagnostic fault codes will not be transmitted if the EF line is not functioning, however, the engine will operate normally.
PCM – IDM Communications Fault Detection/Management

KEY ON ENGINE OFF – VOLTAGE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED WITH IGNITION KEY “ON” ENGINE OFF)
Test Points Spec. Signal Comments
#96 to #91 0.6 +/- 0.1 v CI signal Less than .5v indicates an open between the PCM and the IDM. 12 volts indicates an open in the PCM or breakout box
#95 to #91 0.6 +/- 0.1 v FDCS signal  
#48 to #91 1 to 4 volts EF feedback With the key on, EF has a 83 hz. digital signal that will measure 1-4 volts w/DVOM

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH BREAKOUT BOX INSTALLED, IGNITION KEY SHOULD BE IN THE OFF POSITION)
Test Points Spec. Signal Comments
#96 to #91 > 1000 ohms CI signal Less than 1000 ohms indicates a short to ground either through the harness or internal in the PCM or IDM. Disconnect the IDM and measure to ground. If short still present, disconnect the PCM and measure to ground. If short still present, repair harness
#95 to #91 > 1000 ohms FDCS signal  
#48 to #91 > 1000 ohms EF feedback  

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED, IGNITION KEY SHOULD BE IN THE OFF POSITION)
Test Points Spec. Signals Comments
#96 to #16 < 5 ohms CI signal Resistance from PCM connector to IDM connector
#95 to #17 < 5 ohms FDCS signal Resistance from PCM connector to IDM connector
#48 to #4 < 5 ohms EF feedback Resistance from PCM connector to IDM connector
#91 to #2 < 5 ohms SIG Grd Resistance from PCM connector to IDM connector

KEY ON ENGINE RUNNING (AT LOW IDLE) – VOLTAGE CHECKS – INTERMITTENT FAULTS (CHECK WITH BREAKOUT BOX INSTALLED AND ENGINE AT LOW IDLE) (MONITOR SUSPECT LINES WITH VOLTMETER AND WIGGLE APPROPRIATE WIRES AND CONNECTORS WHILE ENGINE IS IDLING)
Test Points Spec. Comments
#96 to #91 5 – 8 volts CI signal (0 to 12 volt digital signal), monitor engine RPM w/Fluke 88 in TACH mode
#95 to #91 1 – 1.5 volts FDCS signal, 40 – 50 hz. – 0 to 12 volt signal
#48 to #91 .5 – 1.5 volts EF signal, 40 hz. – 0 to 12 volt signal

DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DTC Descriptions
1663 FDCS high or low resistance in the circuit detected during engine off test, OCC * test (REPAIR THIS FAULT FIRST).
1667 CI high or low resistance in the circuit detected during engine off test. OCC * test (REPAIR THIS FAULT FIRST).
1219 CI signal stuck low, harness or internal circuits of IDM shorted to ground (intermittent problem, historic fault only).
1218 CI signal stuck high, harness or internal circuits of IDM shorted to voltage source (intermittent problem, historic fault only).
1668 IDM feedback (EF) (83 hz. frequency transmitted during key ON, engine OFF) not detected.
* OCC = Output Circuit Check

V REF Voltage Reference

 
V REF Voltage ReferenceG00423779
Circuit Functions

The VRef circuit is a 5+/-.5 volt power supply from the PCM that provides power to the three wire engine and vehicle sensors and provides a benchmark or reference voltage for the PCM.

Fault Detection/Management

There is no fault detection, specifically to diagnose the VRef signal directly, but if there is a VRef circuit fault, the sensor(s) in the section of the circuit affected may set an out of range high or low code. Multiple high or low codes are usually an indication of a VRef or in some instances a Signal Ground fault condition.

A VRef signal intermittently shorted to ground will cause the PCM to reset and will be indicated by an engine stumble or stall condition. This will cause the glow plug lamp and relay to recycle.

A VRef signal continuously shorted to ground will cause a no start condition.

V REF Voltage Reference Fault Detection/Management

CONNECTOR VREF VOLTAGE CHECKS (IF MULTIPLE FAULTS SET REMOVE AND MEASURE VREF AT SUSPECTED SENSOR CIRCUITS)
Sensor Test Points Spec. Comments
ICP B to Grd 5 +/- .5 v Check VRef at suspected sensors one at a time. Identifying which sensors do not have VRef and which ones share common VRef feed will more quickly help isolate the area of a short or open circuit.
EBP B to Grd 5 +/- .5 v If disconnecting a sensor causes VRef to be present at a circuit that had previously lost VRef it is likely that the disconnected sensor had shorted VRef to ground.
CMP B to Grd 5 +/- .5 v  
MAP B to Grd 5 +/- .5 v  
AP/IVS 3 to Grd 5 +/- .5 v  
BARO 2 to Grd 5 +/- .5 v  

CONNECTOR CHECKS TO GROUND (B-) (CHECK WITH SENSOR CONNECTOR(S) DISCONNECTED AND IGNITION KEY OFF, ALL ACCESSORIES OFF)
Sensor Test Points Spec. Comments
ICP B to Grd > 1000 ohms Resistance < 1000 ohms indicates a short to ground. If a short to ground condition is identified, remove all sensor connectors are connected to VRef and PCM to determine if short is in a sensor, PCM or wire harness.
EBP B to Grd > 1000 ohms If the short is identified in the harness, remove the intermediate connectors and measuring to ground will identify which part of the harness the short is located in.
CMP B to Grd > 1000 ohms  
MAP B to Grd > 1000 ohms  
AP/IVS 3 to Grd > 1000 ohms  
BARO 2 to Grd > 1000 ohms  

HARNESS RESISTANCE CHECKS (CHECK WITH BREAKOUT BOX INSTALLED ON HARNESS ONLY)
Sensor Test Points Spec. Comments
ICP B to #90 > 5 ohms The measurement is taken from the sensor connector to the PCM 104 pin connector. Resistance greater than 5 ohms indicates high resistance or an open in the VRef supply circuit.
EBP B to #90 > 5 ohms  
CMP B to #90 > 5 ohms  
MAP B to #90 > 5 ohms  
AP/IVS 3 to #90 > 5 ohms  
BARO 2 to #90 > 5 ohms  

SUPPLEMENTAL DIAGNOSTIC PROCEDURES

Camshaft Timing

Probable Causes

Camshaft gear to crankshaft gear assembled out of time.

Procedures
  • Bar the engine over by hand until pointer on camshaft position sensor (CMP) is aligned with the machined timing slot on the crankshaft damper.
  • Remove CMP sensor and view timing disk through the CMP hole in the front cover.
  • If the engine is on the compression stroke for #1 cylinder, a narrow sync vane will be observed directly in the middle of the CMP sensor hole.
  • If the camshaft timing is either one tooth advanced or retarded, the narrow vane will appear approximately 1/8″ from either the upper or lower edge of the hole.
  • If no narrow vane is visible, the engine may not be on the compression stroke for #1 cylinder. Temporarily install CMP sensor, bar the engine over 360° until the CMP sensor pointed and the line on the crankshaft damper are aligned and re-inspect for the narrow vane on the timing disk.
Timing Pointer Aligned with Mark on Damper
Timing Disk (Camshaft Timing Correct)
Timing Disk (Not on Cyl. #1 Compression Stroke) Rotate Crankshaft 360°

Combustion Leaks

NOTE: Combustion gas observed in engine coolant in overflow tank or surge tank.
Probable Causes

The most probable cause if combustion gas leakage to the cooling system is past the lower nozzle sleeve in the cylinder head. A blown head gasket or porous cylinder wall may be possible, but will normally occur under circumstances such as evidence of engine overheating or a very high mileage engine that has not had proper coolant conditioning.

Procedures
  • Plug in block heater to warm coolant.
  • Pressurize cooling system to 14 PSI.
  • Remove valve covers and glow plugs.
  • Observe glow plug holes while barring engine over by hand to see if coolant is flooding the top of the piston and escaping out the glow plug hole. (If the leak is slight, pressure may have to be left on overnight and the engine inspected the next morning.)
  • When the suspected nozzle sleeve is isolated, drain coolant and remove and replace the nozzle sleeve as per the service manual.
  • Retest after repair to confirm repair.
Injector Sleeve – Combustion Gas Leak Path
  • Very slight leaks may require higher pressure to be isolated.
  • Plug in block heater to warm coolant.
  • Remove valve cover and glow plugs.
  • Remove cap from overflow tank (1994/95 F-Series) or surge tank (1995 E-Series, 1996 E & F-Series).
  • Rotate the crankshaft on the cylinder to be tested so that the valves are shut. (Or remove rocker arm pedestals to close valves.)
  • Install the compression adapter Ford (014-014-00931-1) Navistar (ZTSE 4292) in the glow plug bore and adapt gauge end to accept shop air pressure (100 to 160 PSI).
  • With shop air applied observe surge tank or overflow tank for escaping air. If the nozzle sleeve is leaking, air will escape into the cooling system when shop air pressure is applied and be seen as bubbles in the surge/overflow tank.
  • When suspected nozzle sleeve is isolated, drain coolant and remove and replace nozzle sleeve as per the service manual.
  • Retest after repair to confirm repair.
Pressure Check for Combustion Leaks

Coolant In Lube Oil

Probable Causes

Oil cooler bundle or “O” ring damage, front cover porosity, cylinder head porosity, crankcase porosity, nozzle sleeve leakage.

Procedures
  • Plug in block heater to warm coolant.
  • Remove oil pan plug, oil filter and glow plugs.
  • Pressurize cooling system to 14 PSI.
  • Observe/inspect rear of oil cooler (where oil filter was mounted), oil pan plug for coolant or air pressure escaping.
  • If coolant/air leak is occurring from header at the oil filter mounting header, the oil cooler assembly should be removed and inspected or pressure tested.
  • If the coolant is escaping out of the oil pan drain plug, remove valve covers, inspect the cylinder head area under the valve cover and welch plugs in cylinder heads for coolant leakage.
  • If no leaks are found, remove engine and oil pan, block off coolant inlet, outlet and heater hose connections. Pressurize the cooling system with 14 PSI of regulated air pressure.
  • Inspect bottom end of crankcase for pressure leaks.
  • If no leaks are found, remove front cover and inspect gaskets and sealing surfaces.
  • Retest after repair to confirm repair.

Coolant Overtemp

Probable Causes

Gauge error, low coolant level, plugged radiator, wrong radiator, stuck thermostat, no thermostat, defective water pump, broken belt, fan clutch slippage, wrong or damaged fan blade.

Procedures
  • Inspect radiator (1994/95 F-Series) or surge tank (1995 E-Series, 1996 E & F-Series) for correct coolant level.
  • Inspect fan blade, shroud, belt and radiator. (Verify correct part numbers.)
  • Monitor EOT Engine Oil Temperature with the NGS New Generation Star tester (1995 calibrations and later) and compare to dash temperature reading of coolant temperature. During operation, oil temperature is normally hotter than coolant temperature. If oil temperature is less than 230°F when the engine is at operating temperature and the dash gauge indicates an overtemperature condition, the dash gauge sender unit or gauge is suspect.
  • Monitor engine coolant temperature with a manual gauge or a thermocouple installed in the port in the water pump for the existing sender and confirm an overtemperature condition.
  • Remove and inspect thermostat, check for opening temperature.
  • Remove radiator and have flow checked at radiator shop.
Cooling System

Excessive Fuel Consumption

Probable Causes

Inaccurate record keeping or tank filling, winter blend or #1 fuel, high expectations.

Heavy loading (GVW), low rear axle ratio, large frontal area, prolonged idle times, accessory usage (PTO’s et.), tire size.

Brake drag, Fan clutch engagement, transmission slippage/shifting, fuel tank plumbing and venting, intake or exhaust restriction.

Incorrect or defective thermostat, faulty (EBP) Exhaust Back Pressure operation, oil aeration, fuel system leaks, base engine performance loss.

Procedures
  • Review customer records and fueling procedures. Fuel consumption determined from only one tank of fuel is susceptible to significant error because of filling procedures and vehicle application differences during operation. Accurate fuel consumption must be measured over time, preferably over four tanks of fuel with a record of what the vehicle was towing or doing during that time.
  • Loss of fuel economy is normal if winter fuels, kerosene or #1 diesel is being used.
  • Review vehicle specifications to determine if fuel consumption is normal for type of application and use of vehicle. (Compare consumption with similar vehicles in same application)
  • Conduct all tests on the Performance Diagnostic Sheet. These tests will test the following engine/chassis systems and determine if the following systems are functioning or if particular conditions are present. Intake and exhaust system, fuel delivery and filtration system, high pressure fuel system and injector operation, turbocharger and exhaust back pressure operation, oil aeration, base engine condition and electronic control system condition. If all tests are passed, the engine is operating normally.

Fuel/Oil Dilution

Probable Causes

If a substantial amount of fuel is in the oil, the cause may be a leaking tandem lift pump. A leaking nozzle sleeve or injector tip may cause fuel to contaminate the engine oil but may be identified as a performance problem. A porous cylinder head may also cause fuel to contaminate the engine oil but would only be likely in a very low mileage vehicle.

Procedures

Verify oil contamination. Oil contaminated with diesel fuel will have a diesel fuel odor and will cause the oil level in the engine to “grow”.

If the oil has a heavy diesel fuel odor and the oil level on the dipstick has increased over time it is possible that the tandem lift pump is leaking fuel into the crankcase.

Fuel Pump: Possible Fuel To Oil Leak Paths

Fuel In Coolant

Probable Causes

Injector sleeve (Upper section of sleeve to fuel galley).

Procedures
  • Plug in block heater to warm coolant.
  • Remove fuel return lines at regulator block.
  • Pressurize cooling system to 14 PSI.
  • Observe fuel return lines, injector bank with fuel to coolant leak will push fuel or air out of it’s return line.
  • Remove injectors on suspect bank.
  • With cooling system pressurized, observe upper injector sleeve to head fit for leakage.
  • After repair re-pressurize and test to confirm repair.

Low Oil Pressure

Probable Causes

Inaccurate gauge reading, low oil level, oil dilution (fuel), stuck oil pressure regulator, scored/damaged oil pump, rear main galley plug, broken or missing piston cooling jets, front cover “O” ring leaks, missing tappet galley plug, missing bearing shells, porous oil reservoir.

Procedures
  • Verify oil level, check to see if contaminated with fuel.
  • Verify oil pressure using a known good mechanical gauge and measuring at the oil reservoir and at the main oil galley. Oil pressure at both points should be 10 PSI minimum @ low idle and 40 PSI minimum @ wide open throttle with the engine at operating temperature.
  • If the difference between the reading on the reservoir and main galley varies by more than 5 PSI, swap gauges and recheck. If the reservoir still has a lower reading , the reservoir is most likely porous and should be replaced.
  • Remove and inspect oil cooler and regulator assembly. Oil regulator should be properly staked in the oil header housing and the regulator piston should be free to move when pressure is applied.
  • Remove, inspect and measure clearances in the lube oil pump. Upon removal of the lube oil pump, inspect the front cover surface for gouging or deep scratching, inspect the oil pump for damage or wear. Using a straightedge and feeler gauge, measure the height clearance between the oil pump housing and the inner rotor and outer rotor. Specification is 0.001″ – 0.003″ (0.02 mm – 0.08 mm). Using a feeler gauge, measure the clearance between the outer rotor and the oil pump housing. Specification is 0.028″ – 0.032″ (0.72 mm – 0.81 mm).
  • Remove the transmission and flywheel. Inspect rear main plate for oil leaks. Massive oil leak could indicate a missing main galley plug. If a leak is identified, remove rear plate and inspect plugs.
  • Remove engine, remove oil pan and inspect for missing piston cooling jets, bearing shells.
  • Remove front cover, inspect for cut or damaged front cover “O” rings, missing tappet galley plugs.

No Start – Dry Reservoir

Probable Causes

To understand the causes of the no start and identify the causes to this problem, it is important to identify the failure mode.

If the engine:

  • “Started and ran approximately 15 seconds and stalled”. The cause may be a lack of oil supplied by the lube system.

Or if the engine:

  • “Did not start and reservoir was found dry”

Possibilities include reservoir leak down: Caused by a leaking check valve in the high pressure oil pump, porous oil reservoir, or reservoir pump down which may occur during cranking and no start conditions caused by CMP circuit or other electronic control circuit failures.

Procedures

This condition assumes that the reservoir was full when the engine start was attempted or when the engine started normally and would stall after 15 seconds of running.

  • Refill the reservoir and verify the start and stall condition.
  • Remove, inspect and measure clearances in the lube oil pump. Upon removal of the lube oil pump, inspect the front cover surface for gouging or deep scratching, inspect the oil pump for damage or wear. Using a straightedge and feeler gauge, measure the height clearance between the oil pump housing and the inner rotor and outer rotor. Specification is 0.001″ – 0.003″ (0.02 mm – 0.08 mm). Using a feeler gauge, measure the clearance between the outer rotor and the oil pump housing. Specification is 0.028″ – 0.032″ (0.72 mm – 0.81 mm).
  • Refill the reservoir and attempt to start the engine.
  • If the engine does not start, perform the procedures in the Hard Start/No Start Diagnostic form. The tests on this form will discern if the essential elements required to start are present (e.g., CMP camshaft position signal, battery voltage, fuel and fuel pressure, ICP injection control pressure, etc.).
  • If the engine starts, the low reservoir problem may be caused by reservoir leak after a prolonged period of not running.
  • Road test the vehicle for a minimum of 10 miles to assure that all air is purged from the injection control pressure system. Check oil level in reservoir to assure that it is full and let sit over night.
  • Inspect oil level the next morning (prior to starting engine) to determine if leak down has occurred.
  • The only paths for leakage is a check ball internal to the high pressure oil pump or through a porous reservoir or front cover. (NOTE: The check ball has been eliminated in MY96 and newer due to a stand pipe added to the reservoir.)
  • Leakage past the check valve in the high pressure pump may be intermittent. The check valve internal to the pump is not serviceable. 1996 and later high pressure pumps do not have internal check valves. If the high pressure pump is suspect, replace it. (Note: The IPR injector pressure regulator valve which is mounted in the pump should not cause a leak down problem and does not require replacement when a high pressure pump is replaced.)
  • Porosity through a reservoir or front cover casting is unlikely. Leakage through a porous casting would also be diagnosed as a consistent problem and should not be a case of intermittent leak down. If porosity is suspected, it is recommended to replace the reservoir first.

PCM Reset

NOTE: Glow plug lamp cycles on/glow plugs recycle/engine stumble die/no accelerator pedal authority until return to idle position.

A Powertrain Control Module (PCM) reset occurs when the PCM momentarily “reboots” or is turned off and on while the engine is operating. If the condition occurs a single time, the engine will momentarily stumble and the PCM will go through a normal key on cycle, including turning the glow plug lamp and glow plugs on and will also attempt to validate the accelerator pedal position. If the pedal is not at the idle position when this fault occurs, pedal authority will not be allowed by the PCM until the accelerator pedal is released and the engine returns to idle.

Probable Causes
  • Momentary loss of power to the PCM or IDM: Defective power relays, shorted or open harness, intermittent connectors, poor grounds.
  • Momentary short to ground of VRef: Shorted harness or connector, defective sensor (sensors that use VRef include – EBP exhaust back pressure, ICP injection control pressure, CMP camshaft position sensor, MAP manifold absolute pressure sensor, BARO barometric pressure sensor, AP accelerator pedal sensor.)
  • Momentary short to ground of injector high side voltage. Under valve cover harness, valve cover gasket, engine harness, chassis harness are all possible sources of short to ground conditions.
Procedures
    • Complete tests #4, #5 and #6 on the Performance Diagnostic Form, this will determine if the PCM has detected any fault conditions that can cause a PCM reset.
      NOTE: If the PCM is unable to perform a KOEO Injector Electrical Self Test (Buzz Test) it may indicate an injector circuit high side short to ground condition. Disconnect the pairs of injectors by removing the connector at the valve cover and attempt to perform the Buzz Test. If the Buzz Test can be accomplished with an injector pair disconnected, the high side short to ground has most likely been isolated to the under valve cover harness corresponding to the disconnected injectors.
    • Check all power and ground connections for the PCM and IDM.
F-Series Power Network Box
  • Monitor VRef (pin #90) and V Power (pins #71 and #97) with the breakout box installed.
  • Inspect the CMP sensor harness connector and the harness (particularly around the idler pulley) for a VRef or signal short to ground condition.
  • Remove and inspect the CMP camshaft position sensor for possible timing disk to CMP sensor contact.
  • If the PCM reset condition is repeatable, disconnect the following sensors one at a time and operate the engine to determine if the reset will reoccur. (EBP exhaust back pressure, ICP injection control pressure, MAP manifold absolute pressure sensor, BARO barometric pressure sensor, AP accelerator pedal sensor.) Inspect each harness, including the connector upon removal.
  • Remove the valve covers and inspect the under valve cover connectors for possible pinching under the valve cover gasket or rub through against the push tubes.
Under Valve Cover Harness Inspection

Rough Idle Diagnostics

Probable Causes

Engine oil (aerated, incorrect grade, low oil level, extended oil drain interval), defective injectors, injector shorts to ground, dual mass flywheel defects, power cylinder problems, valve train problems, low fuel pressure, aerated fuel, exhaust system to cab/chassis ground outs, loose/worn engine mounts, electronic control system faults, poor fuel quality, injection control pressure system problems.

Procedures
  • Verify Complaint – Confirm conditions when complaint is present. For example, does the engine rough idle only when hot, cold, after high speed operation, does it misfire over whole speed range, is there chassis vibration, are there any other conditions or observations present when the engine idles rough?
  • Inspect Exhaust System for Contact with Cab or Bed – Contact between the flat exhaust pipe that comes off of the engine and the cab has been noted. This will transmit engine vibrations to the cab, especially on acceleration when the engine twists on its mounts. It may be improperly diagnosed as a rough idle complaint. Another exhaust ground out area may be in the center of the box area if a fifth wheel has been installed. Here, the underside bracket may sometimes rub on the driveline.
  • Complete all tests on the Powertrain Diagnostic Sheet. Conditions are described that may contribute to rough idle and the reason for performing the test is listed below. (Note: Updating 1994 PCM calibrations to the 1995 will allow the use of the NGS tool and will more easily facilitate diagnostics.)

Factory fill and current recommended service level is 14 quarts of oil with a filter change. F-Series vehicles built in 1994 were initially serviced with 12 quarts of oil, but should have been updates to an F4TZ-6750-E part number dipstick and should now be serviced with a 14 quart fill.

Must meet CG-4 / SH specification.

Intermittent CMP, IDM, ICP, Injector to wiring harness faults may affect engine idle conditions. The PCM may have detected and recorded these conditions.

This test will verify that the injectors are working electronically.

Low fuel pressure will cause the engine to misfire and cause a loss of power.

  • If pressure is low, remove black canister mounted on fuel regulator and remove any debris on fuel screen. Remove fuel regulator from side of fuel filter and remove any material from screen protecting the fuel deceleration orifice.

If fuel pressure is low, this test will determine if the cause is a restricted fuel inlet from the fuel tank.

This test consist of installing a clear line on the return fuel line. Observing the clear line will indicate if return fuel is present and/or if air is present in the return fuel. No fuel return indicates clogged or blocked return screens or orifices which may not allow air to escape from the system and contribute to rough idle.

This will test the functionality of the ICP control system and the exhaust back pressure system. The engine must be up to operating temperature to perform this test.

This will test the contributions of the individual power cylinders. It will only detect a cylinder that is contributing very little. Its primary function is to detect a bad injector, but it is possible it could detect a base engine problem such as broken rocker arm bolts, bent push tube, broken rings or bent connecting rod.

Oil Aeration Test with DVOM 

Aerated oil may cause the engine to idle rough and possibly stall upon de-acceleration. The most likely causes for aeration are insufficient oil level, incorrect oil grade, extended oil drain intervals and low pressure suction leaks.

Before performing oil aeration tests, verify correct ICP sensor reading by monitoring the ICP voltage signal or the NGS PID ICP is zero with the key on and the engine off. The value displayed will measure between .15 to .25 volts with a DVOM or display 0 PSI on the NGS tool.

Oil Quality 

If the oil is aerating due to depletion of the anti-foaming agents in the oil, the problem will be most evident when the engine is hot and after prolonged operation at high engine speeds. During this test, oil aeration caused by engine oil will probably start at a low ICP signal level (1.4 to 1.5 volts or 1024 to 1060 PSI) and increase to a signal level above (1.75 volts or 1270 PSI) after 3 minutes of WOT engine operation.

NOTE: CHANGE OIL (CG-4/SH) AND RE-TEST IF THIS TEST IS FAILED.

Low Pressure Suction Leaks 

If a leak on the suction side is present, engine temperature will most likely have little effect on oil aeration. The ICP signal during this test will most likely immediately measure above 1.9 volts or 1400 PSI during the WOT test and the engine may not achieve an engine speed above 300 RPM during this test. (It is important that all KOER and cylinder contribution tests have been performed prior to this test. A cylinder or injector not functioning will give similar test results.)

To confirm that a low side suction leak is occurring, overfill the engine crankcase with 3 quarts of engine oil, raise the rear wheels 10″ off the ground and rerun this test. If a suction leak is present (oil pickup tube or gasket leak), the added oil will seal the leak and the ICP signal should be in specification.

This test will help discern if erratic rail pressure and an associated low idle concern is caused by the ICP sensor or IPR valve. Disconnect engine harness connector at ICP sensor while engine is at idle. If engine rough idle smooths out, replace ICP sensor. If engine continues to idle rough with harness connector removed, refer to IPR and Injection Control Pressure system diagnostics.

The crankcase pressure test will determine the condition of the power cylinders and base engine.

Compare ICP Pressure of Right and Left Cylinder Head. Pressure differences between right and left cylinder head have been found to cause poor idle and performance complaints. Install an additional ICP sensor in the right cylinder head, connect the EBP sensor connector to the additional sensor, install a breakout box and monitor the ICP signal on the left head and right head. (Use EBP signal pin) with two DVOM’s installed. Compare the measured signal of the right and left cylinder head at low idle, high idle and under a load. The difference between each head should not exceed .2 volts.

To determine if the pressure difference is caused by internal leakage in the cylinder head or by the high pressure pump, block the line feeding the right cylinder head and operate on the left bank only. Then route the line feeding the left cylinder head to the right cylinder head. (The left high pressure line will reach the right head.)

If there are pressure differences between the cylinder heads, leakage is occurring in the lower pressure head (e.g., loose or cross-threaded oil galley drains, injector “O” rings, bad injector).

If the pressure is the same on each cylinder head, the initial pressure difference is caused by the high pressure pump.

Perform compression test to verify base engine condition.

Performing Compression Test
  • If all performance diagnostic tests are performed and no problems are found and the rough idle is present when the engine is hot listen to the flywheel – if noisy replace flywheel.
    NOTE: If a rough idle condition exists after looking at all known diagnostics, remove the valve covers. While the engine is running at idle, at normal operating temperature, look at the injector spill spouts to try and notice any deviation in oil spillage. A direct correlation exists between the amount of oil flow through an injector and the amount of fuel flow out the tip of the injector into the combustion chamber. Any injector with an obvious deviation in oil flow out the spill spouts should be replaced.
  • If no other faults found change injectors.


Diagnose 7-3, Save $10 off $50, Use Code TENOFF73

Smoke

Black Smoke

Air intake or exhaust restriction, exhaust back pressure device closing, turbocharger failure, loose injector, clogging catalytic converter, altitude (very slight black smoke on hard acceleration is normal).

  • If engine has a fuel knock or there is evidence of fuel in the exhaust manifolds, remove exhaust manifolds and inspect for fuel in the exhaust ports. (Suspect loose injectors, missing or damaged “O” ring and copper gasket on bottom.)
  • Inspect air inlet system and exhaust system for possible sources of restriction.
  • Inspect exhaust back pressure (EBP) device at WOT to determine if closing.
  • Monitor EBP signal (PID) with the NGS tool while operating the engine to determine if exhaust back pressure is high.
  • Temporarily remove catalytic converter and operate engine.
White Smoke
No glow plug operation, loose injectors, cold engine, bent connecting rods, low compression, worn rings, coolant leaking into combustion chamber past injector sleeves.
  • In cold ambient temperatures some white smoke is normal until the engine is at operating temperature. Ensure engine is at operating temperature (205°F) prior to verifying a smoke complaint. If the engine is unable to reach operating temperature during a road test, verify thermostat opening temperature (205°F).
  • On a cold engine the glow plug system may remain on for up to 2 minutes after the engine starts to assist in cold smoke cleanup. Perform glow plug diagnostic procedures (test #10) on Hard Start / No Start diagnostic form to verify glow plug operation.
  • If engine has a fuel knock or evidence of fuel in the exhaust, remove exhaust manifolds and inspect for fuel in the exhaust ports. (Suspect loose injectors, missing or damaged “O” ring and copper gasket on bottom.)
  • If air induction system shows evidence of water injection, that can cause hydraulic static lock and bend connecting rods or if the air induction system show evidence of dusting, perform a compression test.
Blue Smoke/Fuel Odor
  • Oil consumption.
  • Loose injectors.
  • If the engine has a fuel knock or evidence of fuel in the exhaust, remove exhaust manifolds and inspect for fuel in the exhaust ports. (Suspect loose injectors, missing or damaged “O” ring and copper gasket on bottom.)
NOTE: When diagnosing smoke concerns from the exhaust, it is sometimes helpful to loosen the exhaust manifolds and observe which cylinder(s) generates the smoke. This can help identify the scope of the problem. Example: smoke for all 8 cylinders may be due to fuel quality (gasoline in fuel?) but smoke from only one cylinder would not be fuel quality.

Oil Consumption Diagnostic Tips

Probable Causes

There is no single cause. Oil consumption diagnostics are more efficient with an organized procedure.

Procedure
  • Ask the customer the rate of oil consumption and accumulate time or mileage on the engine.
  • If you have an engine with under 3,000 miles with an oil consumption in the range of 100 miles per quart, check the “O” rings and injector tip seals.
  • If you have an engine with over 5,000 miles, check the color of the fuel in the fuel filter housing by draining a small amount into a clear container. A sign of “O” ring damage is fuel discolored in by-passing an injector “O” ring.
  • Inspect the air intake, cleaner, and element for possible restriction or dust by-pass.
  • Perform the turbocharger boost test. (Item #3 on the FCS form 8600)
  • Inspect the intake side of the impeller wheel on the turbocharger for signs of dirt/dust ingestion or damage. Specific things to look for are rolled over edges of blades or broken blades. (Note: Slight traces of oil are normal.)
  • Pull the exhaust side of the turbo loose. Inspect the exhaust side of the turbo wheel. The surface of the exhaust side should have a sooty appearance. Turbine blade damage is evidence of a defect. A damaged blade will lead to bearing failures. Wetness on the exhaust side is a potential sign of bearing failure.
  • Perform a crankcase pressure check. A pressure of 6 inches of water may indicate possible wear problems with pistons or rings
  • Perform an engine compression check.
  • If the cause has not been established, check injectors for condition of the “O” rings seals and for condition of the copper seal at the injector tip. If seal damage is noted, replace the seals. If no cause for oil consumption is found replace the injectors.

External Oil Leak Diagnosis

Probable Causes

Most oil leaks occur at a seal. Oil flows downhill. Start looking for the leak at the top front of the engine and work toward the rear and then down the back of the block. The majority of suspected main seal leaks are actually oil flowing down the back of the block from the engine valley. The engine receives an ultraviolet leak detector in the factory oil fill to assist you in leak detection before the first oil change. Use a black light as a first step.

Procedure
  • Oil leaks flow downhill. Start looking at the top for anything that leaks in the “V” of the drains to the back and down the rear of the engine.
  • Visually inspect plugs, fittings, and hose clamps.
  • There is no high pressure oil at the head gasket. Replacement of the head gasket seal is not likely to repair a leak.
  • Check for loose connections and missing “O” ring seals.
  • If a leak is suspected at the high pressure pump, inspect the mounting gasket for imperfections in the seal bead. Replacing the high pressure pump is not a suitable repair for an oil leak. Replace only the gasket. The gasket is torque sensitive. The correct torque is between 17-19 lb-ft.
  • A slight film of oil and dust at the junction of the halves of the turbocharger is normal. It does not call for service action unless it is dripping.
  • A small amount of oil in the intake deposited by the positive crankcase ventilation system is normal.

7.3L DIT TECHNICAL SERVICE BULLETIN (TSB) ARTICLES

  • 94-23-15
    • LOSS OF POWER – 7.3L DIRECT INJECTION TURBO DIESEL – INCORRECT MAP SENSOR
    • MIL – CODES 128 AND 845 (94MY) OR P0236 AND P0238 (95-97MY) – 7.3L DIRECT INJECTION TURBO DIESEL – INCORRECT MAP SENSOR
  • 95-5-19
    • HESITATION – STUMBLE – LACK OF POWER – IMPROPER OIL DIPSTICK – VEHICLES WITH 7.3L DI TURBO DIESEL BUILT FROM 2/9/94
    • IDLE – ROUGH – POOR PERFORMANCE – IMPROPER OIL DIPSTICK – VEHICLES WITH 7.3L DI TURBO DIESEL BUILT FROM 2/9/94
    • OIL – IMPROPER OIL DIPSTICK CAUSES DRIVEABILITY CONCERNS ON VEHICLES WITH 7.3L DI TURBO DIESEL BUILT FROM 2/9/94
  • 95-6-13
    • NO START – 7.3L DI TURBO – IDM MODULE – NO DIAGNOSTIC TROUBLE CODES
    • REDUCED POWER – 7.3L DI TURBO – IDM MODULE – NO DIAGNOSTIC TROUBLE CODES
  • 95-10-7
    • LOW OUTPUT – DAMAGED OIL PICK-UP OR DAMAGED/MISSING O-RING SEAL – VEHICLES WITH 7.3L DI TURBO DIESEL
    • ROUGH IDLE – DAMAGED OIL PICK-UP OR DAMAGED O-RING SEAL – VEHICLES WITH 7.3L DI TURBO DIESEL
  • 95-10-8
    • HARD STARTING AFTER INJECTOR REPLACEMENT – DIPPING INJECTORS IN OIL BEFORE INSTALLATION – 7.3L DI TURBO DIESEL ENGINE – SERVICE TIP
    • ENGINE – 7.3L DI TURBO DIESEL – DIPPING INJECTORS IN OIL BEFORE INSTALLATION – SERVICE TIP
  • 95-10-10
    • ACCELERATOR PEDAL – POOR OR NO ENGINE RESPONSE – 7.3L DIT
    • ENGINE – 7.3L DIT – LACK OF ACCELERATOR CONTROL WHEN MOVING FROM IDLE POSITION
  • 95-14-12
    • ENGINE – 7.3L DIT – MANUAL TRANSMISSION – OIL LEAK – TRANSMISSION COVER PLATE RUBS ON ENGINE OIL PAN
    • ENGINE OIL LEAK – 7.3L DIT – MANUAL TRANSMISSION – TRANSMISSION COVER PLATE RUBS ON ENGINE OIL PAN
  • 95-23-9
    • HESITATION/STUMBLE – POOR SEAL ON INJECTOR O-RINGS – 7.3L DI TURBO – ENGINES BUILT BEFORE 1/3/95 OR BEFORE ENGINE NUMBER 93602
    • IDLE – ROUGH – POOR SEAL ON INJECTOR O-RINGS – 7.3L DI TURBO – ENGINES BUILT BEFORE 1/3/95 OR BEFORE ENGINE NUMBER 93602
    • LACK OF POWER/POOR PERFORMANCE – POOR SEAL ON INJECTOR O-RINGS – 7.3L DI TURBO – ENGINES BUILT BEFORE 1/3/95 OR BEFORE ENGINE NUMBER 93602
    • STALLS – POOR SEAL ON INJECTOR O-RINGS – 7.3L DI TURBO – ENGINES BUILT BEFORE 1/3/95 OR BEFORE ENGINE NUMBER 93602
    • OIL – EXCESSIVE OIL CONSUMPTION – POOR SEAL ON INJECTOR O-RINGS – 7.3L DI TURBO – ENGINES BUILT BEFORE 1/3/95 OR BEFORE ENGINE NUMBER 93602
  • 95-25-12
    • FUEL – FUEL DOES NOT DRAIN OR DRAINS SLOWLY WHEN FUEL DRAIN VALVE IS OPENED – WATER-IN FUEL LAMP ON – VEHICLES WITH 7.3L DI TURBO – SERVICE TIP
    • WATER-IN FUEL LAMP – LAMP ILLUMINATED CONSTANTLY – FUEL DOES NOT DRAIN WHEN VALVE IS OPENED – VEHICLES WITH 7.3L DI TURBO – SERVICE TIP
  • 96-1-8
    • ENGINE – 7.3L DI TURBO – SEALANT – RTV – AVAILABILITY OF NEW SEALANT FOR SERVICING 7.3L DI TURBO ENGINE
    • SEALANT – RTV – AVAILABILITY OF NEW SEALANT FOR SERVICING 7.3L DI TURBO ENGINE
  • 96-3-18
    • HARD OR NO START – 7.3L DI TURBO -1994-95 CALIBRATION
    • HESITATION – 7.3L DI TURBO -1994-95 CALIBRATION
    • IDLE – ROUGH – 7.3L DI TURBO -1994-95 CALIBRATION
    • LOW POWER – 7.3L DI TURBO -1994-95 CALIBRATION
    • MISSES – 7.3L DI TURBO -1994-95 CALIBRATION
    • STALLS – 7.3L DI TURBO -1994-95 CALIBRATION
  • 96-6-7
    • HARD START/NO START/LONG CRANK TIME – F-SERIES BUILT FROM 2/9/94 AND ECONOLINES BUILT FROM 8/94 WITH 7.3L DI TURBO DIESEL
  • 96-6-10
    • ELECTRICAL PARTS – WEATHER PACK CONNECTOR SEALS – VEHICLES WITH 7.3L DI TURBO – SERVICE TIP
    • WIRING – ELECTRICAL PARTS – WEATHER PACK CONNECTOR SEALS – VEHICLES WITH 7.3L DI TURBO – SERVICE TIP
  • 96-10-14
    • STALL – WHEN REVERSE AND/OR MANUAL LOW ARE SELECTED – VEHICLES WITH E4OD TRANSMISSION BUILT PRIOR TO 9/20/95
    • STALL – WHEN REVERSE AND/OR MANUAL LOW ARE SELECTED, OVERDRIVE CANCEL LAMP ILLUMINATED, AND DIAGNOSTIC TROUBLE CODE (DTC) P1728 – VEHICLES WITH E4OD TRANSMISSION BUILT PRIOR TO 9/20/95
    • TRANSMISSION – E4OD – 7.3L DIT ENGINE – OVERDRIVE CANCEL LAMP ILLUMINATED, AND DIAGNOSTIC TROUBLE CODE (DTC) P1728 – VEHICLES WITH E4OD TRANSMISSION BUILT PRIOR TO 9/20/95
    • TRANSMISSION – E4OD – 7.3L DIT ENGINE – OVERDRIVE CANCEL LAMP ILLUMINATED, AND DIAGNOSTIC TROUBLE CODE (DTC) P1728, AND WHEN REVERSE AND/OR MANUAL LOW ARE SELECTED – VEHICLES WITH E4OD TRANSMISSION BUILT PRIOR TO 9/20/95
  • 96-11-13
    • ENGINE – 7.3L DIT – 1996 ENGINE CONTENT REVISIONS – SERVICE TIP
  • 96-16-7
  • 96-17-19
    • FEAD BELT – WEARS, SHREDS, AND/OR COMES OFF – VEHICLES WITH 7.3L DIT ENGINE BUILT 8/94 THROUGH 5/96
  • 96-19-9
    • MISS – VEHICLE MAY STALL AND NOT RESTART – DIAGNOSTIC TROUBLE CODE (DTC) 1298 MAY BE STORED IN MEMORY – 7.3L VEHICLES ONLY – VEHICLES BUILT BEFORE 4/11/96
    • NO START – VEHICLE MAY STALL AND NOT RESTART – DIAGNOSTIC TROUBLE CODE (DTC) 1298 MAY BE STORED IN MEMORY – 7.3L VEHICLES ONLY – VEHICLES BUILT BEFORE 4/11/96
    • STALL – VEHICLE MAY STALL AND NOT RESTART – DIAGNOSTIC TROUBLE CODE (DTC) 1298 MAY BE STORED IN MEMORY – 7.3L VEHICLES ONLY – VEHICLES BUILT BEFORE 4/11/96
  • 96-21-16
    • TRANSMISSION – E4OD – HARSH SHIFTS – F-250-350, E-350, AND CUTAWAY EQUIPPED WITH 7.3L DIESEL ENGINE BUILT BETWEEN 5/15/96 AND 7/8/96 – CALIFORNIA CALIBRATION 6-90P-R11 ONLY
  • 96-22-11
    • AIR CLEANER – DAMAGED AIR FILTER IN SEVERE DUTY CONDITIONS – VEHICLES WITH 7.3L DIT DIESEL ENGINE BUILT THROUGH 5/8/98 – SERVICE TIP
  • 96-26-21
    • VIBRATION – DRIVELINE RESONANCE/VIBRATION BETWEEN 1400 AND 2000 RPM WITH CONVERTER CLUTCH ENGAGED DURING MEDIUM TO HEAVY THROTTLE CONDITIONS – VEHICLES WITH 7.3L DI TURBO ENGINE AND TRANSMISSION BUILT PRIOR TO 11/13/95 (5L13)
    • TRANSMISSION – E4OD – DRIVELINE RESONANCE/VIBRATION BETWEEN 1400 AND 2000 RPM WITH CONVERTER CLUTCH ENGAGED DURING MEDIUM TO HEAVY THROTTLE CONDITIONS – VEHICLES WITH 7.3L DI TURBO ENGINE AND TRANSMISSION BUILT PRIOR TO 11/13/95 (5L13)
  • 97-1-13
    • ENGINE – 7.3L DI – “MOANING” NOISE HEARD AT 2600-3000 RPM – VEHICLES WITH 4X4
    • ENGINE – 7.3L DI – VIBRATION AT 2600-3000 RPM – VEHICLES WITH 4X4
    • NOISE – “MOANING” AT 2600-3000 RPM – VEHICLES WITH 7.3L DI AND 4X4
    • VIBRATION – AT 2600-3000 RPM – VEHICLES WITH 7.3L DI AND 4X4
  • 97-2-14
    • ENGINE – 7.3L DIT – GLOW PLUG START-UP ON-TIME DURING COLD TEMPERATURE – SERVICE TIP
  • 97-2-16
    • LEAK – OIL LEAK AT ENGINE VALLEY PAN AND/OR HIGH PRESSURE OIL PUMP – VEHICLES EQUIPPED WITH 7.3L DIESEL ENGINE
  • 97-5-12
    • IDLE – ROLLING IDLE – SURGE – VEHICLES BUILT 8/96 THROUGH 12/96 WITH 7.3L ENGINE
    • SURGE – ROLLING IDLE – VEHICLES BUILT 8/96 THROUGH 12/96 WITH 7.3L ENGINE
  • 97-6-18
    • LOW RPM – 7.3L DIT ENGINE FAILS TO START – CODE 340 STORED IN MEMORY AND/OR ENGINE FAILS TO ACHIEVE RATED SPEED FOR 2-3 MINUTES AFTER EXTENDED COLD SOAK – F-SERIES BUILT THROUGH 2/9/96 AND ALL ECONOLINES
    • NO START – 7.3L DIT ENGINE FAILS TO START AFTER EXTENDED COLD SOAK
    • RUNS POORLY – ENGINE TEMPERATURE COLD – RUNS OK WARM – 7.3L DIT ENGINE
    • STALL – ENGINE TEMPERATURE WARM – WILL NOT RESTART UNTIL COOL – 7.3L DIT ENGINE
    • STALL ON DECELERATION – DURING COLD AMBIENT TEMPERATURES – 7.3L DIT ENGINE
  • 97-7-7
    • HARD START – EXTREME COLD AMBIENT TEMPERATURE – VEHICLES WITH 7.3L DIESEL ENGINE
    • NO START – EXTREME COLD AMBIENT TEMPERATURE – VEHICLES WITH 7.3L DIESEL ENGINE
  • 97-7-9
    • WIRING – AFTERMARKET WIRING ALTERATIONS – SERVICE TIP
  • 97-9-20
    • NOISE – “MOANING” AT 1500-2000 RPM – 4X4 VEHICLES WITH 7.3L DIT ENGINE
  • 97-11-18
    • FUEL SYSTEM – 7.3L DIRECT INJECTOR (DI) TURBO DIESEL – NO RETURN FUEL FLOW TO FUEL TANK – BEGINNING WITH VEHICLES BUILT 2/9/94
    • LOW PERFORMANCE/LACK OF POWER – 7.3L DIRECT INJECTION (DI) TURBO DIESEL – NO RETURN FUEL FLOW TO FUEL TANK – BEGINNING WITH VEHICLES BUILT 2/9/94
  • 97-12-11
    • COOLING SYSTEM – COOLANT LEAK AT REAR OIL COOLER HEADER – VEHICLES WITH 7.3L DIT ENGINE – VEHICLES BUILT FROM 9/1/95 THROUGH 10/31/95
    • ENGINE – 7.3L DIT – COOLANT LEAK AT REAR OIL COOLER HEADER – VEHICLES BUILT FROM 9/1/95 THROUGH 10/31/95

OASIS SPECIAL SERVICE MESSAGES

OASIS 

ONLINE AUTOMOTIVE SERVICE INFORMATION SYSTEM SPECIAL SERVICE MESSAGES

  1. SSM NUMBER: 4102EBP solenoid serviced separately from turbo If you encounter a 1994-95 7.3L DIT engine with an rpm/speed limitation associated with black exhaust smoke, and possibly a Code 478, check the EBP Solenoid (F5TZ-6C673-A). Replace the solenoid rather than the entire turbo assembly. It is serviced separately.
  2. SSM NUMBER: 4249Oil filter torque The torque specification for the 7.3L DIT oil filter has been revised to 27 N.m (20 lb-ft).
  3. SSM NUMBER: 4293Check clamps and connections at turbo If you have a report of an exhaust smell in the cab of the 7.3L DIT, check the clamp on the turbo down pipe to turbocharger. Also, check inlet pipes to turbocharger and manifold for loose connections or exhaust leaks. Tighten as necessary. Be sure not to position the clamp to crease a grounding issue.
  4. SSM NUMBER: 4301Normal condition – blue smoke on restart after idling For 7.3L DIT engines, blue smoke on start up following extended idling with the blue smoke disappearing after a short drive at normal operating temperatures is considered normal and no service action is to be performed. White smoke on cold start up on 7.3L DIT engines is a normal characteristic. This condition is common to diesel engines and does not call for service action.
  5. SSM NUMBER: 4418Film of oil/dust normal – If not dripping, do not service Seepage of oil between the halves of the turbo and the small amount of oil in the intake deposited by the positive crankcase ventilation system are frequently misdiagnosed as oil leaks on the 7.3L DIT engine. The seal on the turbo allows a small amount of oil to weep through and this may attract a film of dust. If the seal is not dripping, DO NOT ATTEMPT TO SERVICE IT.
  6. SSM NUMBER: 4774Install quality fuel and operate at speed to clean up catalytic converter Investigation of a plugged catalytic converter on a 7.3L DIT engine indicated that a very low grade diesel fuel, probably not intended for highway use, was being used by the fleet. The concern was resolved by draining the tank. purchasing known quality fuel from a local service station and operating vehicle at highway speeds for about 15-20 minutes while the plugged condition cleared. The low power complaint cleared as the converter self-cleaned.
  7. SSM NUMBER: 4808Check for missing oil filter relief valve A missing oil filter relief valve in the rear oil cooler header is a possible cause of a start/stall with no oil noted in the reservoir, rough idle, or irregular oil pressure gauge readings. The three pieces of the valve (spring, fiber washer, and steel washer) can fall out of the rear oil cooler header while removing the oil filter due to the lack of enough retaining stake. If all pieces fall out and are recovered, the proper order to reinstall these pieces is: spring, fiber washer, and steel washer. Stake them back in place. The valve is not serviced separately. If any one piece is missing, the rear oil cooler header must be replaced.
  8. SSM NUMBER: 5005Check for short in circuit #16 – replace fuel heater Some vehicles may come in with Fuse #22 (30 amp) being open. Other symptoms may include stalling, no start, or a “wait to start” lamp that will not come on. If so, check for short to ground in Circuit #16 from Connector C138 (42-pin) to C188 at the fuel line heater assembly with both connectors disconnected. If the circuit checks OK, replace the fuel heater element.
  9. SSM NUMBER: 5011Remove trapped air after repair The cause of codes 1211 or 1212 can be internal or external leaks, a faulty IPR, a faulty ICP, injectors, high pressure oil system concerns, low or improper oil, trapped air, loss of oil pump pressure, or PCM or wiring issues. Make sure trapped air is purged from the high pressure system by running the vehicle hard for 20 minutes after a repair to avoid false codes. Use 1996 PC/ED symptom flowcharts 3, 10, or 17 and record results of checks on the 11×17 Diagnostic Guide. Only run pinpoint tests when directed by the symptom flowcharts.
  10. SSM NUMBER: 10389Aftermarket products may cause severe engine damage There are various manufacturers offering devices to increase turbocharger boost or otherwise increase the power/torque of the 7.3L DIT engine. Many owner’s past experience with products of this type has been very poor. Severe powertrain damage may result form use of these aftermarket products, which will not be covered by the Ford warranty.
  11. SSM NUMBER: 10614Acceptable smoke levels and factors explained White smoke from the exhaust on start up in cool to cold temperatures on the 7.3L DIT and other diesel engines is normal. Acceptable levels could be described as a puff of smoke followed by very light white smoke for the first kilometer (mile) or so. Some factors which will affect the smoke are fuel quality, fuel range (1D, 2D and winterized 2D), temperature, oil quality API rating, and oil viscosity. All engines are now shipped year-around with 10W30 oil from the factory.

AUXILIARY POWERTRAIN CONTROL MODULE (APCM) TSBs

  • 94-19-18
    • PCM (POWERTRAIN CONTROL MODULE) – REPLACEMENT PCM ALLOW FOR SELECTABLE RPM CONTROL – 7.3L DI (TURBO) DIESEL – VEHICLES BUILT FROM 2/9/94 THROUGH 8/29/94
    • STALLS – 7.3L DI (TURBO) DIESEL – WHEN OPERATING PTO AT IDLE – VEHICLES BUILT FROM 2/9/94 THROUGH 8/29/94
  • 95-15-12
    • AUXILIARY POWERTRAIN CONTROL MODULE (APCM) – 7.3L DIT – AVAILABLE FOR AMBULANCES, TOW TRUCKS, AND OTHER VEHICLES REQUIRING MANUAL THROTTLE CONTROL
  • 95-15-13
    • AUXILIARY POWERTRAIN CONTROL SYSTEM (APCS) – ENGINE IDLE SPEED DOES NOT ADJUST – 7.3L DI TURBO
    • ENGINE IDLE SPEED DOES NOT ADJUST – 7.3L DI TURBO – SHORTED OR OPEN CIRCUIT TO AUXILIARY POWERTRAIN CONTROL SYSTEM (APCS)

SECTION 00-00: POWER STROKE DIESEL ENGINE – 97-15A 7.3L DI TURBO WORKSHOP MANUAL

APCM MANUAL FOR VEHICLES WITH 7.3L DIT ENGINE

Introduction

This kit provides adaptive vehicle “Charge Protection,” selectable fixed elevated idle operation, and/or ” manual” RPM control. This kit is compatible with IN-CAB ONLY mounting of the operator interface Auxiliary Powertrain Control Module (APC Module). A user programming option allows for deselection of any of the functions.

NOTE: If “power up” RPM control is programmed, elevated idle will occur within a few seconds after the below enabling interlocks are met.

KIT FEATURES AND SPECIFICATIONS
Features Specifications/Display
Enabling interlocks
  • Parking brake engaged
  • Clutch engaged (foot off) or vehicle in PARK
  • Service brake off
  • Foot off accelerator
  • Brake lights connected and functional
Adaptive “Charge Protection”
  • System voltage display
Minimum activation RPM for charge protection
  • 1300 RPM
Maximum charge rate
  • At 1747 RPM
Selectable idle operation with closed-loop engine speed control
  • System RPM display
Programmable RPM memories
  • 4
Programmable engine speed “up” ramps
  • 4 (1 per RPM memory)
Minimum programmable RPM
  • 1300 RPM
Maximum programmable RPM
  • 2500 RPM
Manual RPM control
  • Via slow and fast up and down switches
Multiple means of returning to idle
  • Press brake or clutch pedal
  • Release parking brake
  • Take vehicle out of PARK
  • Deselect APC module function
  • Turn off power to APC module

APC Module Display And Key Description

APC Module Display and Key Description

System Checkout

NOTE: Before programming the system, install module per separate installation sheet.
NOTE: If “power up” RMP control is programmed, elevated idle will occur within a few seconds after the below enabling interlocks are met.
Ensure That Enabling Conditions Are Met
  • Parking brake set
  • Manual transmission
    • Engage clutch (foot off clutch pedal)
  • Automatic transmission
    • Gearshift lever in PARK
  • Foot off brake
  • Foot off accelerator
  • Brake lights connected and functional
Power Supply Check
  • Start engine
    • Observe brief display of “8’s” followed by engine speed
    • Observe steady light next to POWER key and backlighting on keys
NOTE: See Diagnostic Section (Section IX) if any of the above are not observed.
Functionality Check
  • Stop engine
  • Restart engine
    • Observe brief display of “8’s”
  • IMMEDIATELY press CHARGE PROTECT key if “Power Up” Charge Protection is not enabled
    • Observe flashing light next to CHARGE PROTECT key
  • If batteries are fully charged, no high current draw accessories are on, and engine is fully warmed, observe elevated engine speed sound equivalent to 1300 RPM
  • Observe display of nominal system voltage
NOTE: If engine is not fully warmed (glow plugs are on initially after start), very high electrical loads exist, or batteries are significantly discharged, engine speed will be greater than 1300 RPM. If electrical loads exceed maximum alternator output (normal with glow plug operation) a below normal system voltage will be displayed.

You have activated the “Charge Protection” function to do this check. To deactivate this function, do one of the following:

  • Press CHARGE PROTECT key
    • Light next to CHARGE PROTECT key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
  • Press brake or clutch pedal, take vehicle out of PARK, or release parking brake
    • Light next to CHARGE PROTECT key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key
    • Light next to CHARGE PROTECT key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
  • Press POWER key
    • All lights next to keys go out (system is off)

Enabling/Disabling Functions And Station Programming

This unit is shipped with “Charge Protection” Fixed Elevated Idle, and Manual RPM Control activated and “Power Up” Charge Protection and “Power Up” RPM control deactivated. Any of these features can be selected or deselected, either with the engine running or with the key in the “on” position and the engine not running. NOTE: This kit provides single station operation only.

To Enable Or Disable Functions
  • Ensure that light next to POWER key is lit and engine speed is displayed. If not, press POWER key
    • Steady light shows next to POWER key
    • Current engine speed is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL), RPM CONTROL, and CHARGE PROTECT keys simultaneously for 3 seconds to activate programming mode
    • Display shows current station setting
      NOTE: For this kit, this value will always be “1.” It cannot be changed.
    • Decimal point flashes on display
    • “VRMP” and “/\RMP” are displayed if Manual RMP Control capability is enabled
  • Press any arrow key to toggle Manual RPM Control function
    • “VRMP” and “/\RMP” disappear if they were previously displayed (Manual RPM Control will be disabled)
    • “VRMP” and “/\RMP” are displayed if they were not previously displayed (Manual RPM Control will be enabled)
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to proceed to the next step in programming. (To exit this programming mode, see the last paragraph of this section.)
    • “V” flashes in upper right corner of display
    • “CHARGE” is displayed if Charge Protect capability is enabled
  • Press any arrow to toggle Charge Protect capability
    • “CHARGE” disappears if it was previously displayed (Charge Protect capability will be disabled)
    • “CHARGE” is displayed if it was not previously displayed (Charged Protect capability will be enabled)
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to proceed to the next step in programming. (To exit this programming mode, see the last paragraph of this section.)
    • “RPM” flashes in lower left corner of display
    • “RPM” is displayed at upper right if Fixed RPM Control is enabled
  • Press any arrow key to toggle Fixed RPM Control capability
    • “RPM” disappears if it was previously displayed (FIXED RPM Control capability will be disabled)
    • “RPM” is displayed if it was not previously displayed (Fixed RPM Control capability will be enabled)
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to proceed to the next step in programming. (To exit this programming mode, see the last paragraph of this section.)
    NOTE: The “Power-up” modes function only for vehicles with automatic transmission.
    NOTE: If either of the “Power-up” functions were canceled prior to entering station programming, and a change is made to Manual RPM Control, Charge Protect, or Fixed RPM Control enabling/disabling, “BASE” will be indicated on the display.
    • If neither Power-up mode is activated, “BASE” will be displayed
    • If Power-up Charge Protect made is activated, “A CP” will be displayed
    • If Power-up RPM mode is activated, “A Sr” will be displayed
  • Press any arrow key to change to a different “Power-up” mode
    • If neither Power-up mode is activated, “BASE” will be displayed
    • If Power-up Charge Protect mode is activated, “A CP” will be displayed
    • If Power-up RPM mode is activated, “A Sr” will be displayed
    CAUTION: SELECTION OF THE “POWER-UP” RPM OR “POWER-UP” CHARGE PROTECT FUNCTION WILL RESULT IN ELEVATED ENGINE RPM WITHIN A FEW SECONDS OF THE VEHICLE’S ENABLING INTERLOCKS BEING MET.
To Exit Station/Function Enable/Disable Programming Before Completing All Steps
  • Press ACTIVATE/DEACTIVATE (FORD OVAL), RPM CONTROL, and CHARGE PROTECT keys simultaneously for 3 seconds
    • Current engine speed is displayed
To Exit Station/Function Enable/Disable Programming After Completing All Steps
  • Press and release ACTIVATE/DEACTIVATE (FORD OVAL)
    • Current engine speed is displayed after the final programming step
  • Press POWER key
    • All lights next to keys go out (system is off)

RPM Control Usage

The RPM Control function provides elevated (minimum 1300 RPM, maximum 2500 RPM) idle engine speed operation with closed-loop control. When the module is shipped, the four engine RPM memories are pre-set at four intermediate RPM values over the operating range, with a moderate “up” ramp rate. Manual RPM control is available by using the slow and fast up and down keys.

CAUTION: IF “POWER-UP” RPM CONTROL HAS BEEN PROGRAMMED, ELEVATED ENGINE RPM WILL OCCUR WITHIN A FEW SECONDS AFTER VEHICLE’S ENABLING INTERLOCK CONDITIONS ARE MET.
To Activate RPM Control (If “Power-Up” RPM Control Has Not Been Programmed)
  • Start engine and ensure that vehicle enabling conditions are met
    • Steady light shows next to POWER key
    • Current engine speed is displayed
  • Press RPM CONTROL key
    • Steady light shows next to RPM CONTROL key
    • RPM stored in Memory #1 is displayed
  • If any memory other than Memory #1 is desired, press one of the four arrow keys to recall the engine speed stored in that memory
    • RPM stored in memory selected is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to change the engine speed
    • Light next to RPM CONTROL key blinks
    • Engine speed increases to RPM displayed
To Use Manual RPM Control
  • Select and activate a pre-set engine speed in “To Activate RPM Control”
  • Press or hold a single arrow (slow) key or a double arrow (fast) key
    • Next engine speed is displayed
    • Light next to RPM CONTROL key blinks
    • When arrow key is released, engine speed displayed becomes a new temporary set point
To Exit RPM Control
  • Press RPM CONTROL key
    • Light next to RPM CONTROL key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
    • “Power-up” RPM Control, if enabled, is canceled for the current ignition cycle
  • Press brake or clutch pedal, take vehicle out of PARK, or release parking brake
    • Light next to RPM CONTROL key becomes steady (system is still in RPM Control mode)
    • Engine speed returns to vehicle idle
    • Engine speed stored in most recently selected memory is displayed
    • “Power-up” RPM Control, if enabled, is NOT canceled. If vehicle enabling conditions are re-established, RPM Control will be re-engaged
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key
    • Light next to RPM CONTROL key becomes steady (system is still in RPM Control mode)
    • Engine speed returns to vehicle idle
    • Engine speed stored in most recently selected memory is displayed
    • “Power-up” RPM Control, if enabled, is canceled for the current ignition cycle
  • Press POWER key
    • All lights next to keys go out (system is off)
    • “Power-up” RPM Control, if enabled, is NOT canceled. If APC is repowered, and vehicle enabling conditions are met, RMP Control will be re-engaged

RPM Memory Re-Programming

Programmable engine speed is limited to a minimum of 1300 RPM and a maximum of 2500 RPM. The four RPM memories are pre-set at four intermediate values within the operating range. These setpoints can be changed with the engine running the following method.

To Re-Program An RPM Memory
  • Select and activate the memory you wish to re-program
  • Tap or hold a single arrow (slow) key or a double arrow (fast) key until desired engine speed is reached
    • New engine speed is displayed
    • Light next to RPM CONTROL key blinks
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key and top arrow key simultaneously
    • New engine speed is stored in memory
To Exit RPM Memory Re-Programming
  • Press RPM CONTROL key
    • Light next to RPM CONTROL key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
  • Press brake or clutch pedal, take vehicle out of PARK, or release parking brake
    • Light next to RPM CONTROL key becomes steady (system is still in RPM Control mode)
    • Engine speed returns to vehicle idle
    • Engine speed stored in most recently selected memory is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key
    • Light next to RPM CONTROL key becomes steady (system is still in RPM Control mode)
    • Engine speed returns to vehicle idle
    • Engine speed stored in most recently selected memory is displayed
  • Press POWER key
    • All lights next to keys go out (system is off)

Charge Protection Usage

CAUTION: IF “POWER-UP” CHARGE PROTECTION HAS BEEN PROGRAMMED, AUTOMATIC ELEVATED ENGINE RPM WILL OCCUR WITHIN A FEW SECONDS OF THE VEHICLE’S ENABLING INTERLOCK CONDITIONS BEING MET.
To Activate “Charge Protection” (If “Power-Up” Charge Protection Has Not Been Programmed)
  • Start engine and ensure that vehicle’s enabling interlock conditions have been met
    • Steady light shows next to POWER key
    • Current engine speed is displayed
  • Press CHARGE PROTECT key
    • Light next to CHARGE PROTECT key blinks
    • Engine speed increases
    • Battery voltage ramps up (if necessary) and is displayed
To Exit “Charge Protection”
  • Press CHARGE PROTECT key
    • Light next to CHARGE PROTECT key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
    • “Power-up” Charge Protection, if enabled, is cancelled for the current ignition cycle
  • Press brake or clutch pedal, take vehicle out of PARK, or release parking brake
    • Light next to CHARGE PROTECT key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
    • “Power-up” Charge Protection, if enabled, is NOT cancelled. If vehicle enabling conditions are re-established, Charge Protection will be re-engaged
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key
    • Light next to CHARGE PROTECT key goes out
    • Engine speed returns to vehicle idle
    • Current engine speed is displayed
    • “Power-up” Charge Protection, if enabled, is cancelled for the current ignition cycle
  • Press POWER key
    • All lights next to keys go out (system is off)
    • “Power-up” Charge Protection, if enabled, is NOT cancelled. IF APC module is repowered, and vehicle enabling conditions are met, Charge Protection will be re-engaged

Alternative RPM Memory Re-Programming And Ramp Rate Re-Programmin

The engine speed setpoints stored in the four memories can be reset in one of two ways: (1) While in RPM Control mode with the engine running as described in this section either with the key on and the engine off or with the engine running. In addition, the ramp “up” rate for each memory can be reset. This is the rate at which engine speed will increase when a new setpoint is activated in RPM Control mode. The ramp “up” rate for each of the four memories is preset at 1/2 of the maximum allowable acceleration rate. NOTE: The ramp “down” rate cannot be reset.

To Re-Program RPM Memories And Ramp Rates
  • Ensure that light next to POWER key is lit and current engine speed is displayed. If not, press POWER key
    • Steady light shows next to POWER key
    • Current engine speed is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) and RPM CONTROL keys simultaneously for 3 seconds
    • Lights next to POWER and RPM CONTROL keys blink
    • “RPM” blinks in lower left corner of display
    • Engine speed stored in Memory #1 is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key and an arrow key simultaneously to select a memory other than Memory #1 to reprogram, i.e..
    • Second arrow key – Memory #2
    • Third arrow key – Memory #3
    • Bottom arrow key – Memory #4
    • Engine speed stored in selected memory is displayed
  • Press or hold an arrow key until desired engine speed setpoint is reached (single arrows provide slow changes; double arrows provide fast changes)
    • New engine speed is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to set engine speed for selected memory and proceed to ramp rate programming
    • /\RMP blinks on display
    • Vertical and horizontal lines show degree of ramp
  • Press or hold arrow keys until desired engine speed ramp up rate is reached
    • Vertical and horizontal lines on display show engine speed ramp up rate (as the rate increases, more lines are displayed)
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to set ramp up rate for selected memory
    NOTE: The ramp “down” rate cannot be reset.
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to return to RPM memory re-programming. Another memory can be selected and re-programmed if desired.
To Exit RPM Memory And Ramp Re-Programming
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) and RPM CONTROL keys simultaneously for 3 seconds
    • Light next to RPM CONTROL key goes out
    • Light next to POWER key goes to steady state
    • Current engine speed is displayed
  • Press POWER key
    • All lights next to keys go out (system is off)

Diagnostics

DIAGNOSTICS
Problem Action
APCM functions but control screen is blank
  • Reprogram the APCM with the latest level calibration
No backlight on ACTIVATE/DEACTIVATE (FORD/OVAL) key or POWER key
  • Check power and ground lines
When trying to enter a mode, light next to RPM CONTROL key or CHARGE PROTECT key blinks briefly but does not stay lit
  • Ensure that enabling conditions are metParking brake engaged, Clutch engaged (foot off) or vehicle in PARK, Service brake off, Foot off accelerator, Brake lights connected and functional
  • With APC module turned off, use NGS Tester to determine if there are any brake or clutch pedal fault codes
  • For non-speed control vehicles (1995 MY only): PCM may be incorrect. For manual vehicles, processor catch-word must be SOD4 or laterFor F250/F350/E350 automatic vehicles, processor catch-word must be TEE5 or later. For Super Duty vehicles, processor catch-word must be PRY4 or later. The catch-word tag may be located on the vehicle “A” pillar or on the PCM itself.
Display reads CErr for 5 seconds before normal display activation
  • Check communication linesOne may be open or shorted
Display reads CErr
  • Check communication linesBoth may be open
  • Check vehicle model yearMay be pre-1995 (module will not function in earlier model vehicles)
Display reads CrSd
  • Check communication lines
  • If communication lines are OK, replace APC module
Display reads EErr
  • APC component defective – Replace APC module
Display reads AErr
  • APC component defective – Replace APC module
Connector Wiring

Installation Instructions For APCM Kit

  1. Remove contents of box and examine contents for correct component qualities.
  2. Using the four (4) screws provided (Item #11), attach the APC Module (Item #12) to the Module Bracket (Item #10). Torque screws to 1.6 – 2.0 Nm.
  3. Snap U-nut (Item #9) onto one end of the Bracket (Item #10) with conical nut projection pointing toward the inside of the angle. (Refer to sketch.)
  4. Attach the Rear Angle Brace (Item #8) to the Module Bracket Assembly using one of the Screws (Item #6) provided. Do not fully tighten at this time!
  5. Place Clip (Item #5) around Instrument Panel Support (Item #3), with the flat part of the Clip tangent to the bottom side of the Instrument Panel Support. (Refer to sketch.)
  6. Remove the two (2) Instrument Panel Attachment Screws (Item #4) as shown.
  7. Place APC Module Assembly under Instrument Panel (Item #1) in position under Ash Receiver Door (Item #2) and attach to flange using the two (2) screws (Item #4) that were removed in Step F. Torque screws to 2.5 +/- 0.4 Nm.
  8. Making sure that the Clip (Item #5) is above the Brace (Item #8), attach the components using the Screw (Item #6) and the Nut and Washer (Item #7) as shown.
  9. Tighten the M6 Fasteners (Item #6) to 12+/- 1.8 Nm.
  10. Attach Wiring Connector (Item #13) to mating connector under Instrument Panel and attach the other end to the APC Module.
APC Module Installation

APC Module Usage

NOTE: IF SYSTEM IS PROGRAMMED FOR “POWER-UP” RPM CONTROL OR “POWER-UP” CHARGE PROTECTION, FUNCTION WILL BE ACTIVE WHENEVER THE ENABLING CONDITIONS ARE MET.
To Deactivate “Charge Protect” Or RPM Control
  • Press lighted key for function in use
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key
  • Press POWER key
  • Press brake or clutch pedal, take vehicle out of PARK , or release parking brake
NOTE: To deactivate “Power-up” RPM Control or “Power-up” Change Protection, use any of the above methods. However, note that pressing the lighted key for the function in use or the ACTIVATE/DEACTIVATE (FORD OVAL) key will necessitate a key-off/restart cycle to regain the “Power-up” function. Pressing the POWER key does not cancel the “Power-up” function. It will still be enabled if the POWER key is pressed again.
Enabling Conditions
  • Parking brake set
  • Foot off clutch or gear shift lever in PARK
  • Foot off service brake
  • Foot off accelerator
  • Brake lights connected and functional
“Charge Protect” Activation (If “Power-Up” Charge Protection Has Not Been Programmed)
  • Press CHARGE PROTECT key
    • Light next to CHARGE PROTECT key blinks
    • RPM increases
    • System voltage is displayed
Fixed Speed RPM Control Activation (If “Power Up” RPM Control Has Not Been Programmed)
  • Press RPM CONTROL key
    • Steady light next to RPM CONTROL key
    • RPM stored in Memory #1 is displayed
  • If any memory other than Memory #1 is desired, press one of the four (4) arrow keys to recall the engine speed stored in that memory
    • RPM stored in memory selected is displayed
  • Press ACTIVATE/DEACTIVATE (FORD OVAL) key to activate
    • Light next to RPM CONTROL key blinks
    • Engine speed increases to RPM displayed
Manual RPM Control
  • Select and activate a preset fixed engine speed
  • Press or hold “up” or “down” single arrow (slow) or double arrow (fast) key
    • New engine speed is displayed
    • Light next to RPM CONTROL key blinks
    • When key is released, RPM displayed becomes new temporary setpoint
  • To save new setpoint, simultaneously press and hold top arrow key and ACTIVATE/DEACTIVATE (FORD OVAL) key for 2 seconds

OBD II GLOW PLUG DIAGNOSTICS (CALIFORNIA)

Diesel On Board Diagnostics II Systems

Comprehensive Component Monitor
Glow Plug Monitor

California and all Econoline vehicles utilize a Glow Plug Monitor (GPM) system designed to locate failed glow plugs or failed wiring in the glow plug system. Diagnostic Trouble Codes (DTCs) indicate which bank has failed glow plugs or failed glow plug wiring.

Glow Plug Operation And Concern Diagnosis Explained

Econoline and California F-Series 7.3L DI: Useful information on troubleshooting fault codes on the glow plug monitoring system. The glow plug system is monitored when the glow plugs are commanded “ON” for over 30 seconds and battery voltage reads between 11.8V and 14V. You can monitor glow plug amps by using the NGS PIDS GPCTM, GPMR and GPML. DTC P1395 or P1396 will set either on the bank that is reading less than 32 amps or the bank that is reading at least 8-1/2 amps lower than the other bank. Loose or fitting pins on the circuit connectors causing high resistance or high resistance glow plug(s) on the opposite bank could also be the cause. Each bank should draw more than 32 amps with not more than 8-1/2 amps difference between banks. DTC P1391 or P1393 will set when the monitor indicates that all four (4) glow plugs are not being powered on that bank.

Possible Causes

Open glow plug circuits, glow plug relay, glow plugs or monitoring circuits(s).

Both DTCs P1391 and P1393 together will set when the monitor indicates that all eight (8) glow plugs are not being powered.

Possible Causes

Open in all glow plug circuits, glow plugs, glow plug relay, fusible links or all three (3) monitoring circuits. If KOEO on demand DTC P0380 is also set, a problem on the glow plug relay triggering circuit will cause all three (3) DTCs to set.

The GPM system uses two low resistance shunts. One shunt conducts the current to the glow plugs in the left cylinder head and the other shunt conducts the current for the right cylinder head. Three sensing wires measure the voltage drops across the shunts when the glow plugs are operating (the voltage drops are proportional to the current in the shunt). The voltage drops are measured after the glow plug current stabilizes (approximately 30 seconds). Therefore, this system only checks for glow plug operation when oil temperature and/or altitude conditions cause the glow plugs to stay on for 30 seconds or more and system voltage is between 11.8 and 14.0 volts.

GPM System Diagram

A menu pick on the NGS tester KOER Glow Plug Monitor Test allows 30 second operation of the GPM system independent of oil temperature or altitude.

The GPM also checks the added sensing wires for out of range readings. These checks indicate a shorted or open sensing wire, or a glow plug relay failure by setting DTCs. The DTCs are stored in continuous memory when a fault is determined, and the Malfunction Indicator Lamp (MIL) is illuminated on the second drive cycle if an OBD II fault is detected. The 49 state Econoline vehicles use the GPM system and hardware to detect faults but do not illuminate the MIL.

The glow plug relay coil is checked for opens or shorts as part of Comprehensive Component Monitoring.

The following is an example of some of the input and output components monitored by the GP monitor. The components monitored belong to the engine system.

  1. Inputs:
    1. Engine Oil Temperature, Barometric Pressure Sensor (BARO)
  2. Outputs:
    1. Glow Plug Relay (GPR), Glow Plugs
  3. The MIL is activated after a fault is detected on two consecutive drive cycles, if the fault detected affects emissions.
The contents of HotShotsSecret.com, such as text, graphics, images, and other material contained on the Diagnose Your Diesel section are for informational purposes only. Always seek the advice of your mechanic or other qualified professional with any questions you may have regarding your vehicle’s condition.

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