I agree with posts by Cathedral Club and Tech II. Verifying are the injectors putting out any fuel and are the injectors getting the right power and voltage and pulse with is critical. Will the injectors fire and put out fuel with manual firing them with 12 volts by hand and then do they spray fuel or not when using the truck wiring is what I was suggesting to verify with the bucket test. If they spray fuel or dribble gas when cranking tells you are all the cyl getting enough fuel or do some just dribble gas or put out nothing when cranking. I think you said they are getting power at the connector but on the 5.3 has 12 volt constant power and uses ground to pulse the injector.
If you haven't already done it, I suggest you verify each injector will manually fire with 12 volts applied manually using the hose and carb cleaner like I suggested earlier. Then verify do any srayy fuel in a bucket bucket when fired by the trucks wiring. You may need to test each connector one by one by just using a hose and carb cleaner with that injector powered by trucks wiring when cranking. Then that tells you is it a problem with the injectors or with the wiring in the truck not getting fire to the injectors. I know sombbody said earlier the injectors need almost exactly 60lbs or more to fire and maybe they are right. My 5.3L probably has different injectors but I cleaned them using a lot less less pressure than 60 lbs pressure and they sprayed out carb cleaner fine when fired manually. Because the firing to the injector is pulsed, I'm assuming you probably cannot get a correct voltage reading on the injector using a VOM becaus it will average the voltage and not respond fast enough. I think you can't watch them pulse without an oscilloscope. You may need to borrow a scope to know are you getting a proper pulse width to the injectors. If they don't spray fuel when manually fired then you need new injectors or need to clean then. If they work manually and don't work when hanging in a bucket using the truck wiring to fire them then you know it is your truck wiring that is not getting correct power to the injector.

I don't know about the 5.7 but I did read on-line that the 5.3 wiring was prone to breaking the wires going to the injectors If you can find one connector that is still working with power to fire and spray fuel then you can check all the injectors ok using that one cylinder wiring and then try to narrow down which fuel injector connectors are not working by checking one by one and try to fix the broken ones by splicing in new fuel injector connectors. The 5.3 fires I think by pulsing the ground and the 12 volt is constant. might want to verify is the 5.7 the same, Don't short the ground to power by checking amperage or resistance or you will likely damage your Control module. those connector. if not getting power to any of the injectors then you may have something wrong causing the fuel to be shut off. Not sure if a TPS needs to be reprogrammed on that vehicle or not but if you don't get power to any of the injectors then you've got to get that fixed.

if you have concerns about frying your computer module then I suggest you look at a video on DX of fuel injectors and how to avoid frying your CCM on UTUBE Schrodingers box.

Sorry Birdhunr, but I've gotta do this as part of policy here: The last post in this thread is over two years old. Please do not post in threads that have no entries less than six months old. Please refer to https://www.gmforum.com/introduction...-first-304557/ for more details.

Thread closed.

Too bad Chevyman95 never came back and told us how it turned out.