This car is a 95 with a 3.4. The fpr definitely went and dumped gas in cylinders 5 and 6, and so I was able to clear them out, went ahead and put new plugs in since I was there and installed the new fpr. There isn't much to the thing it seems (fpr) so I can't think of a problem with the new fpr. The fuel pump primes at key on, which I can hear but does not seem as distinct as before. If I hold open the shrader valve at the rail fuel will spray when the pump primes, but there is no pressure holding even after cycling the key. Car will crank with no start.

 

how much pressure in lbs do you have. sounds like you got a bad regulator.

 

I haven't put a gauge on it, and the regulator is new that I just installed. When I cycle the key a couple of times, even then there is nothing at the shrader valve. The fuel pump was working when the regulator went. Not sure if it's related but I was amazed how much fuel was in #6 cylinder after the regulator went. Can a pump "wind out?" Or can a new fpr be a bad fpr? Also there is fuel at the valve when it primes and I'm holding the shrader open.. And I can hear the pump prime, but does not sound the same to me. I verified voltage at the pump relay. Would VATS disable the pump or starter etc?

 

it does not sound like the fpr is all of the problem. something would have to hold the injector open to fill the cylinder. pick up a noid light and fuel pressure gauge and test pressure and hook up noid light to see if computer is holding the injector open (noid light on all the time) parts store should loan pressure gauge and may even loan noid light. if these things check out as ok then i would pull injectors 5-6 and see if they are leaking. would be very unusual if both went bad at same time.

 

The fuel pump prime will only run for about 5 seconds. \If the engine does not start within that time, the pump will be automatically shut down by the PCM. If the pressure does not hold, then the regulator or the pump could be bad, one or more injectors are leaking, or there is an actual fuel leak

 

Thanks, there just doesn't seem much to the regulator, and it can only install one direction so it's not like I put the thing in upside down. At this point I'd even be GLAD if that were the case. I pulled #6 plug again by the way, which was the cylinder that was full of gas. And even after several times of trying to start the car there was no fuel at all on the plug. Almost looked to dry, so I'm hoping that injector is ok but it obviously was open at some point enough to fill the cylinder. ..When I installed the regulator, I was sure to cross torque it down but started to low on one of the bolts and it started crooked. I just brought the other side down and evened it out, but I wonder if the regulator is off now or crooked in some way? That seem possible?

 

Did you install the little O-ring in the center of the FPR? Without it, Fuel will bypass back to the tank & not build pressure.

 

be best to test fuel pressure with a gauge. low fuel pressure can overload the cylinders nearest the fuel inlet. 5-6, 7-8. 02 sensors see low fuel and opens injectors but fuel only gets to the nearest ones. have you tried using the prime wire, should be a wire coming out of a harness on the passenger side up by the firewall. it should have a female connector on it. 12 volts to it should run the fuel pump. also could try a shot of starting fluid to the air intake by the throttle body and see if it tries to run.

 

Got to it today and the fuel pump is sending 40psi on a gauge, and drops to ten after a couple of minutes. I've tested the fuel pressure before when troubleshooting and nothing was suspect at the rail, and the pressure held for a couple of hours. clinebarger, I think that's it!! I saw the rings that came with the regulator which included O-rings for the injectors, since GM calls for the fuel rail to come out for the regulator install. I was sure to look at the old regulator and could NOT see where the larger O-ring had it's home so I disregarded it as needed on the rail some where. So no I didn't install that O-ring! But now it makes sense.. I may have been nicely recirculating the fuel in my tank for a week now. ha So that ring sits on the bottom of the valve?

 

Ok so these O-rings are actually different sizes, and I can't figure out where the ring goes on the fpr. Of course I pitched the other one after I looked at it. But I'm almost certain I didn't see a ring on it but may have missed it. Where does the O-ring go on??