Technical Service Bulletin: 1994-1998 5.9 L Cummins Hard Start


Reference Number(s): 18-06-98, Date of Issue:  February 27, 1998

Model(s): 1994-98 Dodge (BR/BE) Ram Truck

Group: Vehicle Performance

Bulletin No.: 18-06-98

Date: February 27, 1998

NOTE: This information applies to the 5.9L Cummins Mechanically Injected 12 Valve Diesel.



Hard or no start complaints can be caused by many conditions. The following points will help in diagnosing hard start concerns.

  1. Low fuel pressure or air entering the fuel system.This can cause a low rpm miss/instability, white smoke, hard starting, or low power. Basic fuel system diagnostics should be followed. Technical Service Bulletin 14-07-96 should be referenced when diagnosing fuel concerns.
  2. Loss of fuel system prime.
  3. Incorrect starting procedures.In ambient temperatures below 15° C (60° F), the throttle should be partially depressed after engaging the starter. If the engine will not start, full throttle should be applied. Hard starting in temperatures above 15° C (60° F) can be affected by too low an idle speed. Lower idle speeds increase the need to depress the throttle to start the engine.
    NOTE: DO NOT exceed a maximum cranking time of 30 seconds at a time when hard starting is experienced.
  4. Injection pump timing.Retarded (late) injection pump timing affects starting and excessive white smoke in ambient temperatures of -6° C (20° F) or below. See INJECTION PUMP TIMING SPECIFICATIONS INFORMATION TABLE  for a list of all injection pump timing specifications.
  5. Intake manifold heater.The intake manifold heater grid affects starting in severe cold weather. Verify proper preheat cycling of the grids by following the diagnostic procedures listed in the applicable service and diagnostic manuals.
  6. Fuel heater.Number two diesel fuel can gel in temperatures of -12° C to -6° C (10° to 20° F). For hard start/no start conditions in extreme cold temperatures, inspect for waxing in the fuel filter element. If waxing is found, diagnose for fuel heater operation in the appropriate service and diagnostic manuals.

Model Year/Trans Intercooled CPL Nominal Timing
89-91 all trans no 804 1.40 mm +/- .05 mm
91-93 all trans yes 1579, 1351 1.25 mm +/- .05 mm
94-95 MT yes 1816, 1550 5.80 mm +/- .1 mm
94-95 AT yes 1959, 1815, 1549 5.80 mm +/- .1 mm
95 AT yes 1968 4.40 mm +/- .1 mm
96-98 MT yes 2023, 2175 5.10 mm +/- .1 mm
96-98 AT yes 2022, 2174 4.50 mm +/- .1 mm
EGR Equipped 96-98 all trans yes 1863, 2308 4.50 mm +/- .1 mm
The injection pump for 94 and early95 model year trucks P/N R4761366 was superseded to R4798548. If the vehicle has the superseded P/N R4798548, the engine data tag should have been stamped as CPL 1968 and timing specification for CPL 1968 should be used for the superseded pump
The contents of, 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.