Reader Question: My 1993 Ford Mustang LX 5.0, with the key on engine off, I can hear the fuel pump running. It will not stop until I turn the key off all so the car will not start. Is the fuel pump causing this? And why?
I need your help!
When you turn the key to the ON position the fuel pump should “whine” run for about 2 seconds until it build up the needed fuel pressure to start the vehicle. If your pump runs longer than 2 seconds I would suspect that there is not enough fuel pressure from the pump, the fuel pump is leaking fuel internally and cannot build up the proper fuel pressure and the pump should be replaced, or the fuel pressure regulator has a problem and should be replaced.
My guess anyway. I would get the fuel pressure tested with a manual fuel pressure gauge and have someone test the fuel pressure regulator and the fuel pump relay.
Sometimes, a bad fuel pressure regulator will dump the excess fuel into the oil pan, so pull the engine oil dipstick, and make sure your engine is not filling up with raw fuel!