how fast should the fuel pressure drop after turning of the car? Well to be more specific after 15 minutes my fuel pressure dropped from 36 psi from just turning on the ignition to prime the lines then turning it off, to 20 psi..... Is that a leak?, or is that how fast the regulator is suppost to release the pressure?

 

bump

 

Not typically a leak. The only thing holding pressure after the car has been turned off is the fuel pump check valve and the pressure regulator. Chances are the pressure is being released back through the pump and not the regulator. There as been a couple of threads about this also, you might want to do a quick search.

 

im running stock injectors 550sx850s with a 300zx TT fuel pump, and the car has been running very rich, its a brand new ported motor. i have tried to take some fuel out some cells on the pfc, but i cant really get a a/f because im not running a wide band... i fouled out two sets of plugs... in only 20 miles, the car stumbles alot at idle. vac is good. any other ideas

 

does it backfire when you turn the key to on?dont crank just to the on poss.
i had leaky injectors and it would backfire.

 

nope not back fire, at all... I did some search and came to the conclusion that its not a leaking injector, but an ignition problem. i double checked and my fuel pressure only dropped 2 - 4 psi after 15 minutes of waiting watching the fuel pressure guage, i pull out my plugs and only the trailing plugs was wet, the leading were burnt dry

 

Spring for the wideband. Otherwise your just guessing, and that could end badly.

John

 

What is your fuel pressure at idle? If it's over 32psi, it's likely that the fuel pump is overwhelming the stock regulator.

 

i just connected the regulator while the car is down till i get a new set of plugs. didnt have a chance to check it with the car on. ill keep you guys posted