Identifying a Bad Fuel Pump Relay

If you are looking for information on signs and symptoms of a bad fuel pump relay, this article will be a helpful read. A glance through this article will enlighten you enough about them, to identify their failure if it ever occurs.
Just when you think you know everything there is to know about cars and car repairs, a new problem crops up that forces you to know more about the intricacies of its internal mechanism. One such car problem that may bring it to a standstill is a dysfunctional fuel pump relay.

The relay is a part of the car's fuel injection system. The fuel pump supplies the requisite amount of fuel injected during beginning of every engine cycle and is responsible for triggering ignition.

Function of the Relay

If you have a basic knowledge of how does a car work, you'll know that the engine needs a constant supply of fuel during every engine cycle. The function of the relay is to switch on and switch off the fuel pump according to the status of the engine cycle. The moment you turn your key to start your car, the relay switches on to start fuel pump and get the engine cycle going. When you switch off your car, the relay cuts power to the pump, thereby ceasing the engine cycle.


Every car has a unique design and it is not possible to exactly point out the relay location. It is mostly located behind the dashboard or on the engine firewall. It is located in proximity to the fuel pump in the engine assembly. For information about the wiring and location, it's best that you refer to your car manual.


Here are the prime symptoms indicating problems with the fuel relay.

Car Won't Start
If the relay has quit, when you turn on the ignition, the car won't start. As the fuel pump has not been switched on, the engine cycle cannot be initiated because of absence of fuel. To test the relay, all you have to do is see, if the car starts properly. If it does, then you can be assured that it's working.

Erratic Engine Performance
If the engine suddenly shuts down when you are driving, then it may be due to a bad relay with loose wiring that's causing the problem.

Engine Power Loss and Absence of Sound
If your car decelerated suddenly while cruising, then it might be due to a bad relay. When you turn on the ignition, there is a sound that indicates the relay being triggered. An absence of sound followed by a car starting problem indicates that something is wrong with the relay.

Maintaining a personal car problem diagnosis manual and a regular maintenance schedule will ensure that most of such minor problems never arise. A watchful eye that can keenly assess a car's performance will save you a lot of money in the long run.
By Omkar Phatak
Published: 8/14/2010
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