Solved! No power to fuel pump - 2007 Expedition
 

2007 Expedition EL series; 4.6L V-8. 185K miles. Maintained, but not babied.

Wife shut it off at school yesterday and it would not start. No fuel at fuel rail.

Dropped the tank and was surprised to see the fuel pump looked good. Put 12V to it and the pump spins. I firmly believe the pump is good.

Probed the pump connector and there is no voltage at Key On. The relay and fuse work; I can hear the relay cycle at Key On. I swapped out with another relay just in case the relay switch was bad, but no change in results.

I would normally expect the PCM at this point, but I believe the PCM drives the relay, and since it cycles I'm reluctant to just go running around to source another PCM.

My parts guy insisted the vehicle has a Fuel Pump Driver Module, but I do not believe it. We've been all over the truck looking for it with the tank and spare removed, so I'm pretty certain there is not a Driver Module. This forum pretty much agrees a 2007 does not have one. It is the weekend, so I cannot talk to Ford about my problem.

Anyone ever had an issue like this? Do I need to start swapping computers and other expensive parts, or is there any way to diagnose why I have no power at the fuel pump connector?

Thanks for any ideas.

If you have power at the fuse/relay and not at the pump, your gonna have to trace out the power wire and find the fault - prolly a burned out splice/connector in the power wire to the pump.


My understanding is these systems that have a mechanical returnless fuel system do not use a FPDM. They use a pressure regulator located within the fuel pump assembly within the tank. If the MAF under reports the air flow, the PCM ups the fuel pressure using the pressure regulator in the tank to try increase fuel flow to compensate for the under reported air flow. Running the fuel pump at these very high pressures for extended period can over heat the fuel pump electrical connectors and or fuel pump power feed circuit.


Just my $0.02 :-X22

OK – here’s the deal. I’ve been fixing stuff a long time, and I don’t usually miss something simple, but this hooked me like a big tuna and reeled me in. I also don’t embarrass easily, so I will tell you what happened.

No power to the fuel pump connector. No power to the inertia switch. The relay worked as it should and the voltage was correct at the power distribution panel. The fuses (#32 and #71) were both good. After disconnecting and reconnecting multiple terminals, voila! – power to the inertia switch! Connected everything back up and yep – the pump cycled and fuel flowed! So we reassembled everything and fired it up.

It threw a code for the evaporative system, and we figured something must have not been connected properly. Shut it off, cleared the codes and it would not start. You guessed it, no power to the inertia switch. #%@@!!!!

Started rechecking – good power to the relay, etc, etc. 12.45V at the battery. On an impulse, I asked the wife to hit the starter. Voltage dropped to 9.4V while it was cranking. You wouldn’t know it listening to it – it did not sound like a dead battery and the engine was spinning at what sounded like normal speed. Hooked up jumper cables and it started right up.

New battery, fires right up, no codes, wife is happy – everybody’s happy (but tired).

In the future I will make sure to check the battery voltage under load. If this story can help someone else avoid a lot of cussing, it was worth it.