9550

engine on and idling, fuel pressure at 39psi
shut the car off, it drops to 0 right away
it does this when the engine is cold and when it is warmed up
this cant be right?
i would think the pressure would hold?

5.0stanger

You have an aftermarket regulator? Seems to be a common problem with them. It is fine though...you don't need fuel pressure when your car isn't running

projectresto83

You do have a return system so if the regulator allows the fuel to go by when there is no extra pressure or vaccum then you will lose pressure.

mjr46

it's not normal and it should hold pressure,you'll have to narrow the leak down by pinching off the return line then supply line, but from my experience it ends up being a bad check valve in the fuel pump.......the symptoms that may result from this issue can include extended cranking before car fires up,, if you have no probs then don't worry about it now

FivePointOhh

MJR!!!! you may have answered my question. lol.

i have extended cranking before start up. and my fp also drops from 35 to zero in about 1 second after shutting off the engine.

if the FP is replaced does that also take care of that faulty check valve....considering thats my issue?

Joel5.0

Check valve is built-in to the FP, just make sure you do the test by pinching the return line first, to take the AFPR out of the possible causes list.

FivePointOhh

that i'll have to do.

aode08

countless of times have I found the rubber hose inside the tank on the fuel pump with a small hole in it,or crack.

If you decide to drop the tank,clean the ring retainer area, be gentle on the locking ring, as its rusty and nicks,warps, chips, and breaks easily.

Please use a brass punch, or plastic screw driver to prevent the "spark of devastation".

mjr46

Do what Joel5.0 states.........as he states check valve is built into the pump