This guide is here to help you solve your fuel supply and engine woes by helping you to properly diagnose your car’s fuel pump and spot early fuel pump symptoms before it’s too late. Read for more information on faults, solutions, and replacement costs.
Bad fuel pump symptoms
Starting troubles – Though this is normally one of the later signs of a bad car fuel pump, it’s very common. A worn out pump is not able to generate enough pressure to supply enough fuel to start the engine or keep it running. You may only be able to start the car after several attempts.
A sputtering engine – If the motor is sputtering at high speeds, it is usually caused by an interrupted flow of fuel either due to a blockage in the lines or a failing pump.
Power losses or poor acceleration – If there is not enough fuel pumping through for effective ignition, the engine may lose power or cut out while accelerating. Make sure to check the diesel or petrol fuel filter, lines, and the ignition system as well to rule out other causes.
A noisy fuel tank – One of the most noticeable faulty fuel pump symptoms is a loud whining noise coming from the car fuel tank. This could be due to a blockage or mechanical damage.
Poor fuel economy – This may indicate fuel pump problems as the pump may be consuming too much power or pumping too much fuel.
Surging power – On the other hand, if the pump is supplying too much fuel, it could result in random power surges causing the car to surge forwards. This could be caused by a faulty engine control unit or sensor.
Overheating – The pump may start to overheat due to increased strain caused by damaged, worn or blocked components. Moreover, the engine may overheat as a result of excess unburned fuel.
Misfiring – The fuel may ignite too late or fail to ignite at all due to a faulty fuel pump or imbalance in the fuel-air mixture. Make sure to also inspect the injectors and pressure regulator. This could also be caused by air leaks.
How to start a car with a bad fuel pump
While it is recommended to get your car repaired right away, in some cases, you may need to drive it to the mechanic yourself. Please note that if you continue driving with a bad fuel pump, you could end up doing serious damage to your engine. In most cases, it is safer to get the car towed.
Possible methods for starting the car:
Apply external pressure
It may be possible to get the car running by using another source of pressure such as an air pump to create the pressure needed in the fuel tank.
Bypassing the fuel pump
If you know your way around car electronics, you can try bypassing the fuel pump relay using a jumper wire to force the pump to run. However, this is only a temporary solution and you should proceed with caution as it can be dangerous if done incorrectly.
Check the pump relay and fuse
It may be possible to fix the issue yourself at home if it is caused by a simple electrical problem, such as a bad relay or a blown fuse. You can check the fuse yourself by locating the fuse box and finding the designated fuse. There is normally a list inside the box or vehicle’s repair manual. The relay can be tested for resistance using a multimeter and jumper wires.
How much is a fuel pump replacement?
In the UK, a professional fuel pump replacement typically costs around £450 to £500, although some can cost as much as £1200. The parts themselves often cost less than £200. It usually depends on where you are, how old the vehicle is, and the specific make and model of the vehicle.
For example, a Ford Transit fuel pump replacement will likely cost around £550 at a garage, whereas the same replacement for Audi has an average cost of over £700. Replacing or supplying the parts yourself may help to reduce costs.
