My car cranks, but will not start (plenty of gas). KOEO I can hear the pump prime, but I have 0 psi on the guage. I have verified that the gauge works on a different car. Jumping 12v to the fuel pump prime connector yields satisfactory pressure on the gauge, but as soon as the jumper is disconnected, the fuel pressure on the gauge immediately drops back to 0. Is this normal, or should the guage hold pressure even after removing the power from the fuel pump prime connector (similar to koeo, then turning the key off)? If the pressure should be maintained for a while, then I'm assuming this is a faulty fpr correct? The injectors and fuel pump have both been replaced within the past 6 months so I doubt they're bad. I've checked all fuses and they're fine as well. I'm not sure if the fuel pump relay would cause the symptoms I'm experiencing. Any input is greatly appreciated.

 

i had the same issue as you and it ended up that one of the connections on my <1yr old pump had come apart. i pulled the pump, which was easy because of the trap door method, and saw my issue.

 

I cut the trap door as well. I guess I'll be pulling the door and pump to see if anything has come lose.

 

It seems unlikely that it's the pump hardware or wiring when you can get the proper pressure when using the prime connector. Refer to the wiring diagram and see what that connector bypasses.....maybe it's as simple as a relay.

 

The fuel pump prime connector bypasses the PCM pump permit, and the relay.

From Shoebox:

http://shbox.com/1/1995_pcm3.jpg

 

Ok...so after replacing the fuel pump relay and the fuel pressure regulator with new components, koeo the pump primes up and within seconds is back at zero. I've checked the connections at the pump within the tank and they all look ok...
It looks like my less than 6 month old walbro has failed

 

The Walbro pumps really don't seem to be very reliable. Seems that the check valve is a frequent problem. In addition to the fuel pump, check for leaking injectors and a leaking fuel pressure regulator. Or even leaking fuel lines under the car.

 

...I've swapped pumps and have the same issue. KOEO, pump primes for 2 seconds and then the pressure drops to 0 within seconds. Applying 12V to the pump prime connector by the pcm will allow the pump to prime, but as soon as the power is removed from the connector, the fuel pressure quickly drops to 0 as well. The FPR is brand new. I guess I'll lift the rail again and double check for leaking injectors.