#3 Symptoms of bad fuel pump relay

Fuel pump is a major component in your car fuel system to deliver fuel from fuel tank to the car's engine. Without working fuel pump, your car won't start and the engine may stall (you can read about #6 Most signs of a failing fuel pump)

In many cases, bad or failing fuel pump can be happen by many reasons such as blown fuses, disconnected socket and harness, and or a bad fuel pump relay. In this post, i try to give more information about what symptoms could be happen when bad fuel pump relay occurs.

But before that, we have to know about the fuel pump relay is. The fuel pump relay, is an electronic component that you can find in the fuse box located inside the engine bay, or sometimes in other car types, the fuse box can be located below the steering wheel behind dashboard compartment.

Look at the images below, here is an example picture for fuel pump relays in major car types.

But, to choose the right fuel pump relay and location, you must read the owners manual book or service manual for your car because different car type have different fuel pump relay location. So, what happen to the car if the fuel pump relay start to failed? Here, 3 symptoms of bad fuel pump relay may occurs in your car.

1. Engine does not start

The first symptom may behave if the fuel pump relay going bad or failed is the engine does not start immediately. Usually, the engine may still crank when the starting key is turned to start, however it will not be able to start due to lack of fuel.

When the fuel pump relay won't work properly, it may cut the fuel flow from fuel tank to the engine, so there are no combustion happens inside the engine. As a result, your engine does not start even they crank properly.

2. Engine stalls

The next symptom may behave from bad or failing fuel pump relay is the engine stalls suddenly. Yes, bad or failing fuel pump relay will cut off the electric power from battery to the fuel pump motor. As a result the fuel pump motor will stop delivering the fuel from fuel tank to the engine.

When the fuel pump stop delivering fuel, then your car engine will stop and stalls suddenly, even in running conditions.

3. No sound or vibration from the fuel pump

The last symptom may behave from bad or failing fuel pump relay is no sound or vibration from the fuel pump motor. This is the most common symptom from the internal combustion car engine with electronic fuel injection system.

On many cars with electronic fuel injection system, when the starting key turned ON, we can hear and feel the sound and vibration of the fuel pump motor. Little buzzing may come from the fuel tank location because the fuel pump motor start to spin and delivering the fuel to reach the normal fuel pressure for injection.

If the fuel pump relay goes bad or failing, the fuel pump motor will stop spinning an so the sound and vibration from the fuel pump will stop.