This thread was saved without dates. "Around Aug 2004" is estimated from neighbouring threads.
so i hooked up a guage today to see where the stock pressure is so that when i install my fuel rail and fpr i know where to begin at... i always thought stock was about 36-38psi but i got 46psi at idle.. anyone else tested to see what the stock pressure is
mine stock at idle is 28 rising to 38 with a blip to the throttle.
at idle it should be close to 30 psi and if the throttle is pushed down it should go up to 37 psi (Mitchell Repair)
Bart, did you swap in a bigger fuel pump?
When I did mine, the stock one had a built in regulator. This regulator is what keeps the fuel pressure down when it sees boost.
We have a rising rate pressure regulator. When it sees boost, it cranks up the fuel pressure. In stock form, the regulator in the tank will bleed off anything that goes over 37-8 psi.
Without it, fuel pressure is determined by boost :D
no i have stock everything thats why im asking cause it sounds to high ohh and today i checked it again and it was down to 36pis.. hmmm wtf
i looked a little more into detail in my fsm and itsaid the pis should be about 36, no to test it should i disconnect the vac line to the fpr, cause a buddy of mine said i probably should. he has a sr and thats whats the instructions to test pressure state for, but the fsm really doesnt say anyhting
That is weird.
I can't see why you'd want to disconnect the FPR to test fuel pressure. You would want the readings with the FPR connected, otherwise you won't learn anything. The fuel pressure regulator needs the vacuum signal to raise pressure, so with it unhooked, you'll only get idle pressure.
I would only unhook the vacuum signal to the FPR to see if the FPR itself is working.
I can't see why the pressure would shoot up so high. The stock fuel pump won't live long at 40+ psi.
Best I can figure is there's a blockage somewhere, so the pump is working overtime to get the fuel pressure up.
Either that or the pump is on its way out and is just stuck on full pump.
Eventually the FPR can be overcome, so you'll get a ton of fuel coming by all at once.
Now, are you using a real fuel pressure gauge, or just a generic liquid pressure gauge? If the gauge isn't dampened properly, it might spike like crazy when pressure changes.
ya thats what i was thinking about the vac hose.. the gauge im usig is a fuel gauge so spiking is miminal