Signs of bad fuel pump - Symptoms, causes and solutions


The job of a working fuel pump is to supply fuel from the gas tank to the engine at needed pressure. See the signs, causes and how to fix bad or failing fuel pump!

1. Signs of a bad fuel pump

If your car comes equipped with internal combustion engine, there is definitely no way it won’t have fuel pump. A lot of Nigerian drivers sometimes end up in serious financial debt from repair just because they do not put their ears down and observe certain signs or warning of a possible fuel pump problem.


A bad or failing fuel pump will encounter difficulty supplying required fuel to the engine

The job of the fuel pump is simple as well as important. It delivers fuel to the engine from the gas tank at the required pressure needed for performance. The fuel pump is always activated and pressurized when the ignition key is turned on. The sound of a working fuel pump is mostly quiet. Most modern cars feature electric fuel pumps, which are mounted within the fuel tank. That doesn’t mean you can’t see modern cars with mechanical or inline fuel pumps. As a result of the important role this fuel pump plays in your vehicle, any problem with it can give you a serious headache. Check out the most common signs of a failing or bad fuel pump:

  • Whining sound from the fuel tank

The very first sign of a bad fuel pump is loud whining noise coming from the fuel tank. Except you are not observant enough, you should be hearing this sound while driving. These could sometimes be a sign of a damaged fuel pump, insufficient fuel or having a fuel that is contaminated inside the vehicle.

  • Problem starting

You may encounter difficulty when starting the vehicle if you have a failing or bad fuel pump. Anytime the ignition is turned on, the fuel pump also runs. It could get worn out or even get weakened with time. What you should know is that if your car has a weak fuel pump, it may still pump fuel but gives you problem starting the engine due to the absence of required pressure. This why it sometimes takes a lot of effort or cranks before you get the car started.

  • Sputtering of engine

One of the most obvious ways of knowing a bad fuel pump is when the engine sputters at high speed. If your engine sputters before it returns to regular operation when at high speed, it is sending a message to you of a possible fuel pump issue. At this point, the fuel pump finds it hard to ensure a regular fuel stream at ideal pressure to the engine.

  • Stalling at high temperature

When there are multiple issues in a vehicle’s fuel pump, there is a possibility for it to stall. This often happens at high temperatures. Persistent stalling at such temperature level means the fuel pump is deteriorating. This is unarguably common of the symptoms of a faulty fuel pump.

  • Loss of power

When there is a loss of power, it means something is wrong with the fuel pump. The typical scenario is when you feel the vehicle is under stress when carrying heavy load or driving uphill. The engine might shut down due to lack of required fuel to meet up with this heightened demand.


Driving uphill becomes difficult when the fuel pump stops supplying enough fuel to meet the demand

  • Surging of the vehicle

Surging of the vehicle may occur if there is an irregular resistance within the fuel pump motor. This often sends a signal of a possible fuel pump in dire need of repair. Many at times, this surging may feel just like a used gas pedal.

  • Low gas mileage

When you keep visiting the fuel station more often than usual, it might be due to a problem within the fuel pump. This could be that the valve inside the fuel pump is having difficulty opening, which could cause more fuel than required to go into the engine.

>>> A faulty fuel pump is also the culprit of white smoke: Main causes of white smoke from exhaust & how to fix it


You may end up buying more fuel than usual when there is an issue with the fuel pump

2. Causes of fuel pump going bad

The big question here is; what causes a fuel pump to go bad? To know why you find yourself in the fuel pump mess in the first place, there are 3 major causes. These are:

  • Clogged filters

Many at times, these contaminants could lead to filter clogging, hereby restrict the flow of fuel into the engine. This, if not taken care of, might lead to other serious damage in the car.

  • Electrical issue

One of the main causes of bad or failing fuel pump is electrical issues. This happens there are loose connectors, rusted connectors or melted connectors/wirings.

  • Fuel contamination

When corrosion jeopardizes the fuel, moisture and debris within can bring contaminants into the fuel tank.


When you pour contaminated fuel into your car, you are putting the fuel pump at huge risk

3. Temporary fuel pump fix

Ideally, we recommend to our readers to get a bad fuel pump replaced to have peace of mind on the road. However, some situations warrant that you perform a temporary fix on the fuel pump, to get it out of the unsafe location or to get to the closest auto workshop. To get this done, follow these simple tips:

  • Make use of fuel pressure gauge

This method will help get your car started for the time being. It doesn’t require any special technical skill to perform, as it is quite simple and straightforward. Just attach the fuel pressure gauge to the engine of the car and start.

  • Apply external pressure

This is required mostly after you have tried the first method. Since cars with bad fuel pumps find it hard to get enough fuel pressure needed for their running, you may have to apply external pressure to it. This will help supply sufficient pressure to the engine.

  • Maintain a moderate amount of heat

Fuel pump sometimes reset itself without any need for pressure or heat, especially when the vehicle gets cool. At this point, your car might start but it will endanger the performance of other parts. Maintaining its heat level is essential. Do not allow your car to be too cool or hot. Make sure it has a moderate level of heat to get it started and not reduce the performance level of other parts.

Note: these highlighted methods are not permanent solutions to a falling pump. Take your car to an expert for long term solution.

How to diagnose and replace a fuel pump

>>> More tips and advice on Naijacarnews:

4. Common questions about fuel pump & answers

When you are faced with bad or failing fuel pump, there are some queries that usually pop out of your heads. It doesn’t have to be when you have these problems; it could be a way of preventing possible occurrence. A better understanding will prove helpful in necessary situations.

  • How long do fuel pumps last?

Fuel pump can last for more than 200,000 miles (~322,000 kilometers). But you may start seeing the signs of a failing fuel pump from 100,000 miles (~161,000 km), depending on how you use your vehicle.

  • How to test fuel pump?

You can start by attaching pressure gauge at fuel test port. Watch the pressure after you have cycled the key on and off few times. The pressure of a normal fuel pump shouldn’t drop more than 1 or 2 psi after few minutes of being up.


A pressure gauge being used in a fuel pump test

  • Will a bad fuel pump throw a code?

Even though a bad fuel pump could show signs but not setting a code at all. It means you can detect a faulty fuel pump just by using OBD2 scanner or something like that. You had better pay close attention to aforementioned signs or ask for help from a reliable mechanic.

  • Will a car start with bad fuel pump?

Yes, it will, with difficulties though. We have already mentioned a temporary fix for bad fuel pump so you can start your car at such time, but it is advisable to fix it permanently to avoid damages on other connected parts.

  • How does a car act when the fuel pump is going out?

The first thing a car does is to make a loud whining noise from the engine before showing other signs as explained in the first section, such as difficult starting or loss of power.

  • How to start a car with a bad fuel pump

You can temporarily start a car by applying fuel gauge, external pressure and maintaining its heat level. Please refer to our previous part of this post for details.

5. Conclusion

If you are a car owner, it is important you observe these signs of a bad fuel pump in order to avoid any unwanted surprises. Make sure you are 100% certain about the faulty parts before making some repair on your own.

Otherwise, whenever you discover any issue with it, take your car to an auto expert for professional inspection and permanent fix.

>>> You can find more Car care tips and Fuel saving advice on!

Oluwaseun Adeniji