Hi Guys,

I have a 2000 F-150 with 250k on it. For the last few months I've had an intermittent problem. Sometimes the fuel pump would prime when I turn the ignition, other times it would not. I eventually (about 2 weeks ago) changed the fuel pump.

Unfortunately, this was not the problem. It is still doing the same thing, so I began troubleshooting.

I've done a few measurements at the fuel pump relay, here are my findings.

Fuel pump relay contacts have 12VDC
Fuel pump relay coil has no voltage.

I've done a substantial amount of reading, and have learned that the coil will get its 12VDC signal from the ECU (correct me if I'm wrong).

My best guess is a loose connection somewhere, as the problem has been intermittent from the start. So, I'm looking for any advice and hopefully a fuel system wiring diagram.

I've tried jumpering the relay, and the fuel pump does run. By doing this the truck still does not start. So I'm assuming the same signal that engages the fuel pump relay also engages spark? Any idea where I should be looking? At this point the truck has been off the road longer than it has been on, I really need to get this going. Any help is appreciated.

 

Did you swap out the sending unit with the pump?

 

No, the sending unit has not been swapped out.