heydave

I have a 95 f150 with the 300 in it and I can spray gas in the intake and it will start and run very bad only if you pump the gas I checked the fuel pressure and koeo it's 28 with it running it's 50 and jumps up to 55 when given gas. Could this be a bad fuel regulator?

heydave

One more thing when I first turn the key on the pressure jumps to 55 until fuel pump stops running

Manuellabour247

Does it bleed down after the initial prime? If so, how long does it take to drop from the initial 55psi? Key on Engine Off (KOEO)

heydave

As soon as the pump shuts off the pressure drops instantly to 28

heydave

I clamped the return line and tried it and it still went to 50 and as soon as the pump stopped it dropped to 30

Manuellabour247

@fltdriver has the specs for some of the fuel system I think. Check some of the sticky's at the top of the page to see some other checks. "You can call me sean" has a few different things on there.

Chris_1

iTrader: (1)

If it doesn't hold pressure it could be 3 things, Leaky regulator (fuel through the vacuum line) : injector stuck open : faulty fuel pump (either one if you have dual tanks).
Who put the pump in ? It sounds like it has an earlier 4.9 pump (mid 94 back) which ran at 45 to 60 psi.
I believe that 95 and 96 4.9 pumps were changed to run at 30 to 45 psi

heydave

I just bought the truck and was told they put a new pump in it sure where it came from. I have been reading everywhere the pressure should be very high though

joshtowal

Key On Engine Off 50 - 60 psiKey On Engine Running 45 - 60 psi

joshtowal

Take the line off right before the fuel filter and test the pressure there. If it holds steady KOEO, your pump is alright. If it drops out, your pump is bad or theres a hole in a line by your tank. If it holds pressure, your problem is either your regulator or injectors.