FPR help
 

I checked the fuel pressure with a gauge and don’t have any pressure with the key in the on position. I have to crank the engine to get pressure, with the engine running it's @ 44psi. The car had been backfiring and stalling, will a fpr not let fuel to the motor without the car on? Do you know where I can get a fpr for a good price? ..

Is an Autozone fpr any good?

Did you check the fuel pressure with the vacume line disconected?
Do you have any way to check codes, or get a datalog?

When you turn the key to "on", but don't start the engine, the pump primes for two seconds and then shuts down. In that interval, the pressure should reach at least 40psi. Then it should hold that pressure for a period of time. Are you saying the system shows no pressure at all when the pump primes? If it never shows any pressure, could be the regulator or the fuel pump. If it shows an initial pressure, then bleeds down quickly, could be the FPR, the check valve in the fuel pump or leaking injectors. Pull the vacuum line off the FPR and feel for wet fuel.... that is a sure sign of FPR failure.

The pump will not restart until you attempt to start the engine. When the PCM sees the pulse pattern from the Opti, it starts the pump and injectors. Apparently you have some residual fuel pressure after the pump primes, or the engine would not start. Once its running, check the fuel pressure with the vacuum line off (41-47psi meets spec), then with the vacuum line reconnected (pressure will drop into the 30's, depending on your cam and manifold vacuum).

With it running, tape the gauge to the windshield, take it out on the road and go WOT/max RPM, and the fuel pressure should hold at least 41psi at all times when the throttle is wide open.

The FPR works by closing down in the fuel line that returns to the tank. You should always get some pressure when the pump is running, but if the FPR can't close down on the return flow, you will not have enough pressure.

I checked the fuel pressure with the vacuum hose connected and disconnected it was @ 34 psi both times. I turned off the car and the pressure went to 0 with the vacuum connected and disconnected. No fuel on or around the fpr. I cannot drive the car because it's getting worse. Not sure what it is....

Check the pressure with and without the vacuum line attached, as I already suggested. If it holds 34psi with the line, and 44psi without the line (you didn't confirm that you got the 44psi reading with the vacuum line on or off????), not likely the culprit is the FPR. Could be a weak pump, leaking injectors, or a faulty check valve in the fuel pump. Again, testing it at WOT, as I already described, would tell you if the fuel pump is healthy.

If you just follow the procedure, it will point to the problem.

Im trying to follow this so i will give it a shot. The car when you start it goes to 34 psi with and without the hose (make sure you get vacuum) connected. Then it will go to zero after you turn it off. How long does it take to go to zero? Mine does it, but it takes 10-20 minutes and some a lot longer. I would strongly suggest a factory replacement fpr as opposed to an aftermarket one if it is bad. I say this on a lot of parts like O2's, maf & other sensors.

I checked the pressure with and without the vacuume and it stays @ 34 psi. As soon as I turn off the car it looses the pressure. I installed a walbro pump, it was working for two days and now I have these problems. I haven't got a chance to drive the car, when I do I will post the results...
Thanks for the help guys.

Finding out you just replaced the pump would have really helped in solving this. I would definately look into the pump being the problem. I have replaced a few but not on the LT1. I guess something came loose or was installed incorrectly making the fuel go straight back into the tank. Sounds like some sort of check valve. Did you drop the tank or use the trap door method which would make checking it a breeze?

I did the back door meth. I looked into the bucket and gas was in it. I'm going to take my car to a mechanic i'm tired trying to solve this :cry: