F150 fuel pump?????
Asked by ttrammell2002 Jul 17, 2014 at 03:22 PM about the 1991 Ford F-150 XLT Lariat 4WD LB
Question type: Maintenance & Repair
I have a 91 F150, 4x4, auto, 5.0, with duel tanks. I parked it a couple months ago after
I bought a newer truck. went to seel it and now it won't start. Started everytime before.
When I turn the key on I can hear the fuel pump run, and it keeps running. It's suppose
to run for a second then stop right? The engine turns over but it won't fire. I thought it
was out of gas, so I put some in it, and it ran, next day same thing, won't start. Tried
the other tank, same deal can hear the fuel pump running non-stop.
6 Answers
Sounds like the supply line broke. Like it's just circulating fuel within the tank. Can you see fuel hitting the ground?
ttrammell2002 answered 9 years ago
I will check to see if there is any fuel hitting the ground. Just to clarify, when you turn the key on the fuel pump primes its self, then stops right? then of course when you start the engine the pump will run. on mine it doesn't seem to be priming it's self, like maybe it's out of gas, but I know there is gas in the tank.
That's how I always figured they worked. Never torn apart a Ford before. Do you have a port to hook up a fuel pressure gauge? That way you will know if it's working.......
ttrammell2002 answered 9 years ago
well I got ahold of a pressure gauge, and I have 44psi with the key on engine not running. Fuel pump is still running all the time
Well the only thing I can think of is the fuel pump relay is stuck in the closed position, which makes continuous contact, causing the fuel pump to remain on. Have you tried replacing that yet?
that model has a fuel pump mounted on the frame on the drivers side, rear tank has a pump inside the tank, i am not sure but i think that truck has 2 or even 3 relays for the fuel pump's i would 1. check for fuel leaking, all area's. (if no leaks are found) 2. check for a bad (stuck) relay. each relay has a fuse, if you have an owners manual they may be located, if not look on line at a wiring diagram for your truck. >stuck relays are common in older year model's< age and use--wear ,tear, and HEAT get to relay's as they age. always use safety Gear, Good Luck, Mike
