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Fuel Pump Symptoms and Solutions: How to Identify and Fix a Failing Fuel Pump

Image of a diesel fuel pump filling a fuel tank
January 2, 2025

Imagine rushing to work one freezing winter morning, eagerly trying to get your car to start and escape the biting cold, only to be met with noisy trembling sounds or a complete inability to start the engine. It’s terrible but totally plausible, and there are plenty of reasons why it could happen. One of them is fuel pump failure.

A fuel pump is an automotive component designed to efficiently transfer fuel from the vehicle’s tank to the engine. It’s crucial to your car’s ability to move, playing a significant role in combustion cycle. However, a fuel pump is also prone to fail over time and it’s important to know when it’s happening.

Recognizing fuel pump failure symptoms helps you address the problems early on and avoid bigger issues. Read on to learn more about the signs of a bad fuel pump and how to prevent them.

 

What Does a Fuel Pump Do?

Diesel and gasoline-powered vehicles, or those with an internal combustion engine, are equipped with a fuel pump. The pump’s primary function is to supply fuel from the tank to the fuel injector or carburetor, where it mixes with the intake air. The air-fuel mixture then travels to the combustion chamber, which converts it to energy to power the engine.

The type of pump used depends on the type of engine system. Fuel-injected engines typically use electrical or high-pressure mechanical pumps, while carbureted engines use low-pressure mechanical pumps.

Fuel pumps deliver a steady and consistent supply of fuel to the engine. This ensures proper combustion, which is crucial to the vehicle’s overall performance and fuel economy. Without a well-functioning fuel pump, the engine may experience issues such as engine misfires, loss of power and even complete engine failure.

 

Symptoms of a Bad Fuel Pump

A malfunctioning fuel pump can spell bad things for your vehicle. It can damage the vehicle and, more importantly, it makes driving unsafe. Knowing the most common bad fuel pump symptoms can help you avoid issues and address them promptly. So, how can you tell if your fuel pump goes out? Watch out for these signs:

1. Difficulty Starting the Engine

Among all symptoms of fuel pump failure, one of the first signs that car owners notice is the difficulty or complete inability to start the engine. This often manifests when you turn the key and the engine cranks, but it won’t start. When this happens, it could be a sign that there is insufficient fuel getting into the engine, which is an indicator of a failing fuel pump.

2. Engine Stalling or Cutting Out

Unexpected stalling or difficulty maintaining power is another sign of a bad fuel pump, which may be caused by an inadequate fuel supply. Engine sputtering occurs when your vehicle suddenly dies while driving despite having enough fuel in the tank. This is another symptom of a weak fuel pump that can be very dangerous if left unchecked.

3. Engine Surging While Driving

Just as engine dying is a problem, engine surging while driving is an issue as well. This could mean there’s too much fuel being sent to the engine, causing it to suddenly pick up and lose speed. This could be a sign of a failing fuel pump and make it difficult for the driver to control the vehicle.

4. Loss of Power

A sudden decrease in engine power, especially when accelerating, driving in steep inclines or carrying heavy cargo, could indicate an inconsistent amount of fuel is being delivered to your engine.

5. Whining Noises

Low humming noises are common for fuel pumps, but high-pitched whining, whirring, howling or cranking noises warrant immediate attention. If you suspect the noise is coming from the fuel tank, it could be a sign of a worn-out fuel pump.

6. Check Engine Light

Plenty of reasons could trigger the check engine light to turn on and one of them is a bad fuel pump. If you notice your check engine light and have ruled out every other possible reason, your fuel pump may be the culprit. One reason this could happen is a lack of fuel pressure.

7. Poor Fuel Economy

Lower fuel mileage for your usual consumption could be a sign of a malfunctioning fuel pump. Poor fuel efficiency may be due to damaged fuel pump components, causing inconsistent fuel to be transferred into the engine.

8. Fuel Leaks

Damaged or worn-out components in your fuel pump system may lead to fuel leaks either into the engine compartment or directly onto the ground. If you suspect a significant decrease in fuel economy, check for possible fuel leaks as this could indicate a defective fuel pump.

 

Causes of Fuel Pump Failure

Fuel pumps are designed to last a long time. However, as with other engine components, they are prone to wear and tear over time. Being part of a system, they can also be impacted when other components get damaged. While knowing the symptoms of a failing fuel pump is essential, familiarizing yourself with common causes of fuel pump failure is just as important. Below are some of the reasons why your fuel pump could be malfunctioning:

  • Overheating: Running out or consistently having low fuel can damage your fuel pump, leading it to overheat once it runs dry.
  • Contaminated fuel: Dirt, debris, sediments and microorganisms can contaminate your fuel. This can clog the fuel pump and filter and damage the pump.
  • Electrical issues: Blown fuses, a defective fuel pump relay and faulty wiring are common culprits of fuel pump failure. Any of these electrical issues can prevent the pump from receiving power, thus impacting its ability to deliver fuel to the engine.
  • Damaged fuel filter: clogged fuel filter can restrict fuel flow, causing added strain on the fuel pump, which may lead to damage and eventual failure.
  • Dry Fuel: Fuel acts as a lubricant and coolant for the metal-on-metal surfaces inside a pump. When fuel lacks lubricity, the pump can overheat and experience increased friction, leading to premature wear or failure.
  • Wear and tear: Constant exposure to heat and the rigors of daily wear can lead to a damaged or worn-out fuel pump.

 

Diagnosing Fuel Pump Issues

Beyond knowing what to look for in terms of bad fuel symptoms, it’s also helpful to learn how to correctly diagnose fuel pump issues. Spot-check and troubleshoot your car’s fuel pump using these tips:

  • Listen for whirring sounds: A low humming sound when you turn the ignition key means the fuel pump is working. Pay attention to other unusual noises when starting the engine which may indicate a failing fuel pump.
  • Check fuel pressure: Install a pressure tester in the fuel pressure test port. Run the engine and check if there’s enough fuel pressure. Otherwise, your fuel pump may be failing.
  • Examine electrical wirings: Check for electrical faults such as loose or rusted connectors and melted wirings within the system. Use a digital volt meter to test for possible voltage drops and continuity.
  • Inspect the fuel filter: Look for symptoms of a bad fuel filter and possible contamination. Dirt and debris may accumulate and damage the filter, leading to fuel pump issues and engine trouble.
  • Scan for trouble codes: Run an onboard diagnosis using an OBD-II scanner. Check for trouble codes associated with fuel pump failures, such as P0230 for low fuel pump voltage and P0148 for fuel supply error.
  • Conduct a visual inspection: Check for any visible signs of a bad fuel pump, such as fuel leaks or obvious damage to the pump and fuel lines.

 

Preventing Future Fuel Pump Issues

The fuel pump is vital to the engine’s performance and having a defective one can be both a hassle and a danger. To ensure the longevity of your car’s fuel pump, follow these simple tips:

  • Conduct regular fuel system maintenance.
  • Avoid driving with a low tank to prevent overheating and premature wear.
  • Replace damaged or worn-out components immediately.
  • Steer clear of rapid acceleration or harsh braking when driving.
  • Keep your fuel lubricated and the fuel system clean by using high-quality fuel additives.

 

FAQs About Fuel Pump Failure Symptoms

Refer to these frequently asked questions about the fuel pump’s function and failure symptoms.

  • How do I know my fuel pump is going bad? Common signs that your fuel pump is going bad include difficulty starting the engine, engine sputtering and surging, and sudden loss of power.
  • What happens if a fuel pump goes out? Fuel pump failure can lead to engine performance and car drivability issues. It requires immediate attention to prevent further damage and the risks of accidents.
  • Can you drive with a bad fuel pump? While it’s possible, driving a car with a bad fuel pump is highly discouraged. Some symptoms of a weak fuel pump include sudden surging or stalling at highway speeds, which can be dangerous for the driver and other motorists.
  • How long does a fuel pump last? A fuel pump is designed to last up to at least 100,000 miles before it starts showing signs of wear.
  • Where is the fuel pump located? Fuel injection vehicles have their fuel pumps in the fuel tank, while gasoline direct injection vehicles normally have theirs by the fuel rail in the engine compartment. In diesel vehicles most have a lift pump in the tank and a high pressure injection pump under the hood.

 

Keep Your Fuel Pump in Great Condition With Hot Shot’s Secret

The fuel pump plays a significant role in a vehicle’s performance. Without it, it’s impossible to power the engine and safely drive the vehicle. There are several reasons that contribute to fuel pump failure, but there are also ways to prevent this from happening.

Hot Shot’s Secret offers a wide range of products designed to prolong the life of your fuel pump and other system components. Browse our online catalog or contact us for more information.