What should the Fuel Pressure be on a stock 1992 z28 at idle and when its not running . Any help would be great thank you.

 

42-45psi I believe. Mine is 42psi wile running or just with the key on.

Phil

 

well i just tested my car and when the key is on i get between 41 and 42 psi with it runing at a idle i get about 38 so i need to get a fuel pressure regulator but my whole reasoning for these test are due to after driving me car around it dies at intersections and i cant seem to find a issue.

 

Try unhooking the vacaum line at the regulator. at an idle the pressure should rise about 5lbs+- also have you replaced your fuel filter? check and see what the volume of fuel that is beeing pumped is will it fill a 16oz bottle in say 30 seconds? you might have a bad hose or filter that is limiting the flow of fuel?

Just my 2 cents!!!

 

i had just changed my fuel filter about a month ago when the problem had started first thing that was done but problem still is occurring generally when the vehicle is hot. and will not start back up tell it cools back down. now when you say remove it are you saying to leave it off at all times or just for the pressure test only?

 

Leave the fuel filter hooked up but unhook the vacaum line at the regulator and see if the fuel pressure changes. The vacum is to change the spring pressure so that at an idle the car does not run rich.

Unhooking it will give you a clue as to if the regulator is working as it should.
I would check the two lines from the frame rail to the hard line next to the alternator take them off and check for swelling of the rubber that could block fuel of cuts inside.
I have a semi that had a cut in the incide of a hose that after a while of running it would kill the motor. (took forever and LOTS of $$$ to figure that one out)

If you have 35-40 lbs press and good volume it should run the injectors could be a problem when hot but not likely.

I would,
1. Check the press w and w/o vacaum line hooked
2. check the amount of fuel flow
3. check the rubber lines at engine

Does the computer have a code stored? to you have access to a cable for conncting a laptop to the computer and see what happends with the a/f ratio and injector duty cycle as the engine runs...
If you still have problems send me a PM and I can scan the pages for my '88's shop manual that might be of help for you...
Dave

 

The senior members would remind us that an engine needs spark and fuel to run.

Your description of fuel pressure at key-on and at idle seem about right. Your fuel pressure regulator seems to be working correctly.

When the engine dies and you try to start it again, can you hear the fuel pump prime up before you turn the engine over? Check connections at fuel pump relay.

Try to check for spark after the engine dies. I once had a bad ignition module that would stop working only when hot. The engine would just stop running. After a few minutes of cool down, it would start up again. Check connections at distributor and coil.

 

thats what i was planing on doing and yes the fuel pump does in fact prime i had spoke to my father today about it and he also said check the ignition.

 

Regulator sounds fine.
Mine's 43 at prime and 38 running at idle.

Oh and "The senior members would remind us that an engine needs spark and fuel to run."

 

well everything seems to be pointing at a ignition issue . but im wondering if when then fuel pump gets to hot and then stops pumping but still makes the noise . but is that logical?