Sandman94F150

05 5.4L I couldn't get my truck to start the other day, scanner showed no fuel rail pressure, jumped the fuel pump to make sure it was working. worked fine. Hooked the fuel line back up and jumped the pump again to get fuel into the rail. Again KOEO showed no fuel pressure. But it did start. Once running I had 30 psi. let it run for 10 min and it stayed at 30 psi. shut it off for 10 min. Went to start it again and it showed no fuel pressure but it did start again though it took a few seconds. Shut it off for 20 min. Went to start it and again KOEO no fuel pressure. this time it took awhile to start, about 20 seconds. but again once started it stays at 30 psi.
So the longer I let it sit with the engine off the longer it takes to start.
So driving down the road with barely any throttle it stays at 30 psi, once I give it gas it drops below 20. if I really give it gas the pressure will drop below 15 or 10 psi. of course the truck picks up slowly as the pressure increases.

lewissa81

Have you checked the FPDM?
How old is the fuel filter?

Mod (Ret.)

Fuel filter is what I'd suspect first. Long periods of being parked, then difficulty starting is a sign of a clogged/dirty fuel filter.

Sandman94F150

I have replaced FPDM, fuel filter, fuel pump, plugs COP. I will only let it sit for an hour or two before it wont start again.

lewissa81

You could have a wiring issue, or the fuel pressure sensor is faulty. Or even the vacuum line going to the sensor is leaking. I would check those next.

Sandman94F150

Yeah I checked all the vacuum lines.


I decided to take to a mechanic I don't have enough knowledge in electrical


Thanks all