TOOSLO5

Got a fuel pressure issue with my Chevelle that's got me stumped. When I first got the car together and primed pump the FP gauge on the rail would go up to 60 psi and hold. Now the pressure goes up to 60 and then drops off over about 10 seconds. This does not seem to be an issue with a cold start situation but after the car has been driven for a while I have a hard start problem. The gauge still reads the same with pressure dropping off but the crank time is excessive. This also occurs at all levels of gas in the tank. I am running a Walbro 255 pump with a Vette FPR/filter and a stock sumped tank. I am using the original pickup line as the return line back to the tank. The pickup line was bent slightly to direct fuel back towards the sumped area. I have tried a different pump and FPR and the problem is still there.

Anyone got any ideas? This seems like a fuel system issue but maybe someone out there has another idea.

Thanks!

hosspowerinc

iTrader: (22)

How about a fuel pump relay problem?

bczee

iTrader: (12)

Try by-passing the relay or activate the relay without using the PCM to trigger it (just add 12+v to the relay trigger wire) .

this should be just a test to see what static pressure your getting. That should test your system. If it maintanes a steady pressure, then you know it is something else. PCM to the Relay wire, fuse holder, ground (90% of electrical problems are related to bad grounds)?

Rodder

iTrader: (2)

I'd say you have a leak somewhere. Could be anywhere between the fuel pump and the injectors, including an injector or the fuel pump itself.

TOOSLO5

Not a relay problem since the pump always comes on to prime the system when the key is turned to the accy position. You can hear the pump come on, prime, then go off until you start cranking the engine.

As far as a leak goes I didnt think about an injector. I wouldnt think with the pullout only having less than 10 miles on it when I installed it that it would be an injector, but anything is possible. Second pump in the car is new along with the FPR so an injector is about all that is left to check.

jeepinpete

From what I have read, and experienced, the truck injectors can get gummed up if they sit for awhile. Usually it gums them shut, but maybe a bit of crud got in there and has stuck it open? If so, you are fighting a flooded situation. Try starting it with the pedal floored. The computer will go into flood mode and not inject any fuel until the engine starts. If it does start, you certainly have an injector leak...