I had a new fuel pump put on a month ago. I put a fuel pressure gauge on the schraeder valve and turn the key and got 48 psi and then started the engine and got a steady 46 psi while running. I turned the car off and the psi dropped to about 30 psi in 5 minutes. Leaking injector(s)? New FPR too.

Ken

 

Leaving the pressure gauge hooked to the test nipple, find a way to SAFELY clamp off the fuel hoses. If you clamp the larger one and the pressure holds, there is a problem with the anti-drainback valve in the fuel pump. If you clamp the small one (only) and the pressure holds, the FPR leaks. If you clamp BOTH and the pressure still drops, then the injectors are leaking. The system SHOULD hold pressure for 20 minutes, at least, without losing more than about 2 PSI of pressure.

 

Well pinching the fuel lines didn't change my psi drop. I'm thinking its the injector(s). Even while driving, my scanner shows the block learn AND the integrator at 100. Sometimes at idle, the integrator will drop to 90 and sometimes in the 80s. Funny how the ECM does'nt throw a code or anything. Still, it could be a vac leak I have'nt detected yet. Can't you pull the fuel rail out and have someone turn the key to see if you got a leaking injector?

Ken

 

Yep. Undo the Fuel line hold brackets, take the upper plenum off, remove the rail and injectors, and set the rail on something with the injectors hanging from it so you can see them dripping.

I had mine sitting on the radiator all hooked up (minus the fuel injector wire connectors) The system primes right up and you can watch each injector for leaks.

The few times I lost pressure was from a bad cold-start injector o-ring after I installed it wrong I guess, and the rail itself was bad (wouldn't seal against the pressure regulator disk or whatever)

*did have a leaking injector once. I installed my old injectors while the rail was out instead of pulling the new injectors out of the intake. Had one that leaked slightly. Still didn't account for the 35psi drop in 10 seconds.