The pump sounded different due to restricting the output, (normal).

Your maximum output pressure is fine. Your 10 minute leakdown to 71psi is fine. This tells us that if leakdown at the service port drops below 55psi, it's not the pump causing it, and the problem is in the plenum.

Time to remove the plenum and check things out. Could be a leaky injector housing, leaky injector, leaky spider line, internal or external leak at the regulator, etc etc.

 

took a peek inside the plenum (removing the throttle body) no gold spots anywhere, injectors were all replaced 25k ago. if i remove the upper intake, do i have to replace the gasket? it was replaced a year ago with the fel pro, it was done when the LIM gasket was done.

any tutorials on how to take off the upper intake? im more worried about putting stuff back then taking it off, thats the easy part lol

 

Remove the adapter from the fuel filter and connect the fuel line back up. Check pressure and leakdown at the service port and post the results.

 

fpt at service port

key on 55 psi
key off: 58 psi
10 min leakdown: 38psi

obviously that failed miserably. theres no where else around it, the problem has to be in the plenum right? is there one thing that would cause both low pressure and a leakdown? fpr maybe? i know it could be 2 different things each causing low pressure and leakdown but is it likely?

 

Remove the plenum & reconnect the fuel pressure and return lines. Remove the nozzles from the lower intake manifold. Activate the fuel pump and check for leaks at the regulator, the fuel injector metering block, and at each nozzle.... everything should be bone dry while the pump is running. Post your results. On your 2000, you can activate the fuel pump by applying battery voltage to the pump prime terminal located in the underhood fuse panel.

 

is there any thread showing how to remove the plenum, the most ive done was take the TB off. dont wanna mess anything else up lol.

to apply battery voltage to the prime terminal, do i use a jumper to another fuse outlet?

 

Check in the how to section for doing lower intake gaskets, all you'll need is the beginning part of it. And yes, you'll need new gaskets for the plenum and the throttle body, don't reuse the old ones.

Toward the front of the underhood fuse panel, there is a stud with an 8 gauge red wire, jump from there to the pump prime terminal and the pump will run continuously while the jumper is connected.

 

my friend who installed my pump is gonna give me a hand removing the plenum, is there a return line for the fuel?

 

On the top of the injector housing there are two steel lines held in place with a small bracket & two stainless steel nuts. The larger line is the pressure line from the pump, and the smaller one is the return back to the tank.

 

my one friend didnt seem interested in the job, say it was the FPR, how long of a job is it? best guess of course since times vary. if i cant find anyone to help i may have to just take it somewhere, my problem is idk where besides gm who id actually trust, sorta.