fuel pump relay replacement

What does a fuel pump relay do?

The fuel pump relay is the electronic switch that controls power to the fuel pump. It is found on virtually all vehicles with an internal combustion engine and is often located in the fuse box which can be found in the engine bay. The fuel pump relay is also responsible for helping your vehicle to start. The relay activates the fuel pump to pressurise the fuel system as you turn the key.

The fuel pump is a small pump which sends the fuel from the tank to the engine. The pump may be mechanically worked by the engine, but on most modern cars it’s electrically-powered. In this case it’s usually found next to or even inside the fuel tank.

This process of pumping fuel from the tank to the engine is essential in the smooth running of your vehicle, therefore a faulty fuel pump relay will cause major performance and drivability issues with your vehicle.

How often should a fuel pump relay need replacing?

There is no set lifespan of a fuel pump relay, however the relay is designed to last the life of the car, but due to its constant use and the high temperatures it is exposed to, it will not usually last that long. Over time, the fuel pump relay may begin to show signs of wear and will have to be replaced.

The most commonly damaged portions of the fuel pump relay that tend to malfunction first are the coil and contact points. Usually, these parts of the relay will begin to oxidise and rust over time.

The law, vehicle regulations and your MOT

If the fuel system is not working properly, this may result in an MOT fail. Similarly, if a failing fuel pump relay has caused your check engine light to illuminate, this could lead to an advisory or failure.

What causes a fuel pump relay to break?

The fuel pump relay can fail for many reasons, from dust to electrical power surges, or a blown fuse to a fault in the pump. Many things can affect the functionality of the fuel pump relay.

What are the signs of a failing fuel pump relay?

Usually, there a few signs you can look for:

• Poor fuel economy

• Trouble starting your car

• Poor engine performance - stalling, poor acceleration, rough idling

• Check engine light

• Car stops whilst driving

How often should you replace your fuel pump relay?

There is typically no maintenance schedule for fuel pump relay replacement. However, it may not be a bad idea to replace the fuel pump and the relay on an older, high mileage vehicle. Regularly maintaining small components such as the fuel pump relay could save you costly repair bills down the line.

What happens during a fuel pump relay replacement?

During the repair our certified mechanics will:

• Inspect the entire fuel system and test it for any issues

• They will then locate the fuse box, usually found in the engine bay

• If necessary, they will remove the old relay and replace it with a new one

• They will they retest the fuel system and check the fuel pump is working

What is the average life of a fuel pump relay?

There is no set lifespan of a fuel pump relay, however over time, the fuel pump relay can begin to show signs of wear and will have to be replaced. The fuel pump relay is designed to last the life of the car, but due to its constant use and the high temperatures it is exposed to, it will not usually last that long.

The most commonly damaged portions of the fuel pump relay that tend to malfunction first are the coil and contact points. Usually, these parts of the relay will begin to oxidise and rust over time.

Can you drive with a broken fuel pump relay?

It is best to avoid driving with a failing fuel pump relay. If the fuel pump relay has an issue, power may be randomly cut off to the fuel pump, which will cause the engine to stall whilst driving. Problems with your fuel pump relay will also result in frequent stalling and poor fuel economy, problems which are inconvenient and costly. It’s always best to have a faulty fuel pump relay checked as soon as possible to avoid these issues.

What happens if you don't change the fuel pump relay?

If the fuel pump relay has an issue, power may be randomly cut off to the fuel pump, which will cause the engine to stall whilst driving. Problems with the relay may also result in frequent stalling and poor fuel economy, which are both inconvenient and costly.