Fuel pump
Asked by Warchild99 Mar 23, 2019 at 11:39 AM about the 1992 Ford F-150 STD 4WD SB
Question type: Maintenance & Repair
My fuel pump don't work when turning the key.
All fuses work and new relay.
I put a jumper wire under relay and the relay will
click and pump comes on. I pour gas into top of
motor and it will run but only till gas i poured in
runs out. The gas from tank is going to the fuel rail
with lots of pressure but not going through
injectors to motor. Tank and fuel pump kinda new.
Is there something that cuts off the fuel pump
when it cant get gas into motor or is this 2 different
problems i have.
4 Answers
Check for injector pulse when cranking the engine, it may be the ignition module or the stator (especially if it's the one mounted under the distributor they fail quite a bit) at my shop we usually replace both at the same time. A parts store can test the module for you if you pull it off. The pcm is what turns on the relay to power the pump. It's very rare for them (Ford computers) to fail. The pump will only run for about 2 seconds with the key on and engine off. If the injectors don't fire it won't run even with fuel pressure.
Warchild99 answered 5 years ago
I just had autozone test the ignition module. Its good. Ill check the other stuff later. Tired of working on it for now. But its looking like it might be the computer
You should test the wire from the pcm to the relay, make sure it's not a break in the wire somewhere. A wiring diagram would be the way to go, if it ends up having a break somewhere it may be easier to just run a new wire. Like I said the Ford PCMs very rarely go bad.
Warchild99 answered 5 years ago
Yeah it ended up being the computer. I just put the new one in and the fuel pump comes on like its supposed to but the fuel still isn't going through the injectors. Ill check the fuel regulator and injectors later. Truck has been sitting about 6 years. That was a crazy job tracing all those wires and looking at everything in the world. I opened up the old computer and see parts inside burned up. While tracing the wires down i found where the last owner had cut and spliced into wires close the the computer for something. I got it all cleaned up now.