jayk2k3

iTrader: (2)

has anyone ever heard of a fuel pumping acting up?? like at idil the fuel pressure is 40psi, but at 4grand the fuel pressure drops to 10psi. i was told it was problaly the fuel pump, but it only 6months old (cheap fuel pump), could it be the regulator?????brand new fuel flitter, so i know its not that.

F-BIRD'88

"brand new fuel flitter, so i know its not that."

That would be the first thing I'd check.

It's always the new part that fails.

IHI

iTrader: (1)

I hope it's not an O'Reilley's pump??, if so, there's your problem and time for a new one before you get stranded.

jayk2k3

iTrader: (2)

i though it was the flitter, thats why i replaced it. i can hear the fuel pump, staying on, so i guess thats my problem, agree or disagree????

IHI

iTrader: (1)

Disagree. On my work truck I went through 3 O'Reilly pumps within a 1.5yr span. You couold hear the pump prime when you turned the key to the on position, so at face value you would think, hey-the pumps fine. But I hooked up my guage to the fuel rail and it only showed 28psi when it is uspposed to be 45psi minimum. You could dump gas down the TB to start it and it would then idle, but as soon as you gave it gas it'd die. Installed new pump, 60 psi and it ran like a champ.

Same with buddies Tahoe, his oem pump died last year hunting, installed new Oreilly pump since that was only auto store in that town, ran great. 2 weeks ago it went out. Same symptoms, could hear it prime, but did not have psi to keep it running.

Your pump could be doing the same thing, keeping up to a certain rpm, than not having enough psi/volume to keep motor running.

Filter are cheap/quick/easy to change, so try that first to eliminate that out of the equation, probably need a new one anyways, if not it does'nt hurt anything either. If you have another regulator handy you could try that first since obviously it's gonna be cheaper/easier to test than installing a new pump. FPR have been known to go bad also, on the GM trucks you can pull the vacuum line going to the reg and if there's raw fuel in there, the reg is shot. I dont know how these cars came set up, but would be worth a look to check it out.

jayk2k3

iTrader: (2)

ight im pretty sure i need a fuel pump now. one more question would have a hole in the fill neck cause it to be more harder on the fuel pump or fuel pump pressue??? thanks for the info

IHI

iTrader: (1)

From what I've seen the tanks either have a vent that comes out of the fuel ring on top of the tank that vents externally so as not to build up a vacuum inside the tank, or they come with a vented cap.

If the tank has no venting at all, yes it will affect pump performance since it's trying to literally collapse the tank to suck out fuel. Kinda like sucking on a straw in a 20oz bottle of pop wihtout letting any air in. It will collapse the botle walls and force the pop up and out, but if there's air allowed in the bottle will stay intact and pop will come out the straw.

iroczracer07

iTrader: (2)

I knew a guy that had problem with a fuel pressure drop like yours. We found that his fuel pressure regulator diaphram was bad. Replacing it fixed the problem.