Hello. I have a fuel delivery problem with my 1990 F250 (351w), and I'm starting to run out of ideas so I figured I would ask for some help.

The Rundown: Truck will not start, but will fire with starting fluid. Can't hear fuel pump running.

Where I'm at: I checked the fuel pump relay connector and had power so I replaced the fuel pump relay, I figured this was the easiest place to start. Checked for power at the inertia switch and I do have power. I unplugged inertia switch and ran jumper across the terminals, but still no fuel pump. Truck has dual tanks so I checked for power at the interior tank switch (I'm assuming that power runs from the inertia switch to the tank selector switch and then to the pumps). I have power at one of the leads on the selector switch, but I'm not sure what each pin is for. **Note: I don't know if this is a clue to the problem or not, but both fuel tank guages are buried past the full mark, but they are not full. For now I'm going to assume (while not impossible) that both fuel pumps did not fail at the same time and there is another problem. Another note, this truck has been sitting for a couple of years. I've read through some of the other posts and realize that grounds can be an issue with vehicles that sit for a while. But, if it were a ground issue I wouldn't be showing power at the places I have checked...would I? My next step is to start tracing backwards from the pumps. Any suggestions would be appreciated. Thanks!!

 

When you say power are you using a test light or a meter?
Take what a meter says with a grain of salt.
Always use a test light when working with the fuel pumps.

It sounds like you may have lost the ground on the drivers side radiator support.
Also check the small black wire leaving the NEG post of the battery and going to the body.

 

Yes, I'm using a test light. I haven't checked the ground on the core support yet. I thought that since I have power the ground was probably good. Maybe a misconception on my part. The fuel guages being pegged on full indicates a ground problem though. I'll check that tomorrow.