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Hi! So I have a 1988 Firebird I'm trying to swap a gen 3 5.3 ls into. Currently it will run off of starting fluid shot into the intake but I am unable to get the injectors to work properly, I've cleaned all of them and made sure the fuel rails were up to par. It has a pretty much all-new fuel system setup to run 60psi from the pump to the injectors. And I do have 58psi at the fuel rail.
My issue is that the injectors will not open to let it run! When I put my multimeter on the plug it gives me 6V, when I should be getting 12V. It drops to 4V when cranking. If I put my red lead to the hot wire and my black lead to battery negative I get 12V. I know the PCM is supposed to ground the injectors at specific times for it to turn them off and on but I just don't seem to be getting enough ground.
Keep in mind I have a new battery that has 12 + volts. And I've clicked all 8 on and off with a 9V battery to clean them. I can leave my fuel rail up enough to see wether or not they are pulsing while I turn it over and they are not. I do have a flashed PCM with VATS removed that is tuned for my specific setup.
I feel like I have to have a bad ground or something somewhere but I don't know. I've gone through all my grounds and they seem fine. Help?? I'm at my wits end with this thing, so close to having it running.
Thanks in advance!!
(She's not pretty but she's my high-school sweetheart and I plan on bringing her back to her glory days
Do you have power to the PCM - memory keep alive power and PCM operating power - during engine cranking?
Rick
I'm certain I have power to the PCM, never heard it put that way so I'm not sure how to test it exactly. As an update when I test the ground wire on my injectors with my multimeter I get this:
Black to inj. ground, red to batt. Hot: 12.3V (key off)
Same setup but with the key on: 0.1V (like nothing)
Same setup but while cranking: 2-4V.
Here are the pinouts for your 2002 model year truck PCM wiring harness. I suspect that you will discover the source of your problem below. Who built your wiring harness?
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Fuel Injectors Not Working 
