HiPerf_Chevyman

1991 v6 3.1. New Injectors, Fuel pump (bosch replacement). The Car sometimes has a extended crank in the morning, and when hot sometimes it will have a very high idle, 3-4K and slowly come down and starting running on 2-3 cyl's just about to die and sometimes does....

I just checked the Fuel pressure tonite. KOER Its at 43ish PSI and when i rev it, the pressure goes up smooth and gradually to 55 PSI and when i unplug the Fuel Pres. reg. it jumps straight to 55.... After sitting 25-30 Minutes KOEO the pressure rapidly bounces from 5-20psi and settles to about 10. Then we attempt a start, we get an immediate stall, and then a restart and the idle is high and then settles with the about to stall idle with the pressure at and in between 20-55 psi then the pressure slowly calms down to 43ish psi and idles wonderful. Ive got some research to do..... I just wanted to know if anyone has seen this and could pin point the issue.

ex-x-fire

Pull the vacuum hose to the regulator & then watch the regulator port for fuel to come out, it might take a few minutes.

HiPerf_Chevyman

Yea ive done that, and Nothing makes it out..... Ive done it while its running, and after i shut it off I never seen gas. left it unhooked for about 10 minutes..... I watched a video in youtube about it taking over 5 minutes for them to show a Liquid leak.... But other than that, i forgot to add, as soon as the engine is off/key off. the Fuel pressure drops to 0psi. Im not sure if these systems are suppose to drop that quick or not.

ex-x-fire

Time to pinch off the return right after the fuel rail, reprime, & watch for pressure to drop. It could be a leak inside the tank, the hose that connects the pump to the fuel line.

HiPerf_Chevyman

Oh yuck...... These should hold pressure when the pump primes and shuts off right? hmmm. I guess I'll check that tmrw.... yay Thanks for the input.