electric fuel pump

The electric fuel pump is generally used on fuel injected cars. It has a relay under the hood, usually on the inner fender, which supplies 12 volts dc to the pump. It should click every time the key is turned to a forward position. The starter does not have to engage for this to happen. If someone turns the key forward for you, you will be able to hear it clicking under the hood, assuming it works. If it is clicking you can still check it. One of the leads should have no voltage then switch to at least 12 volts when the key is turned. This action primes the pump and builds fuel pressure up so the engine can start. The pump itself is usually located inside the gas tank, so that it is cooled down by the fuel. The fuel pump delivers about 7 psi to throttle body injected engines.

 

Multi point or port injection systems generally use around 45 psi to spray a fine mist of fuel out of the injectors. Also by locating the pump in the tank there is no concern of the pump loosing it’s prime. If located outside the tank it needs to be lower than the tank to gravity feed if it ever runs out of fuel. Sometimes pumps will lock up, or quit spinning. If the fuel pump relay seems to be working check the fuel rail. The rail sits on top of the injectors. The fuel rail normally has a valve on the top, the same style you use to fill your tires up with air. As the key is turned forward you can press gently on the center of the little metal stem and fuel should come spraying out. If no fuel comes out, you need to drop the gas tank and replace your fuel pump.