Fuel Pump Issue. Need Help Bad

[VegasElectrician]

I have an 02 Suburban with a fuel pump issue. The fuel pump went out. I had my neighbor kid swap it out. When he replaced it, he broke the nipple on the vapor canister, (not sure if that’s relevant). He reinstalled the tank and we went to start it up and.... nothing. The gas gauge wouldn't read and there was no fuel going to the fuel rail. We dropped the tank again and I noticed that he installed and adapter on the wiring harness. I disconnected the adapter and plugged it in directly. The gas gauge kicked on, the truck started up, then sputtered out. I checked fuel pressure with the key in the on position. It would start out at 45 PSI, then rapidly drop to 0. I checked the FPR, it was fine. I checked for an injector that might be stuck open, they were fine as well. I returned the pump and picked up a new one. Now, I only get 4 volts to the pump in the on position and no fuel to the fuel rail. I swapped out the FP relay and still, only 4 volts. I bypassed the relay with a jumper and got 12 volts at the pump, but the pump still won’t engage, and the gas gauge won’t turn on either. I tried installing the adapter that came with the last pump and the gas gauge kicked on, but still have no fuel to the fuel rail. All grounds are good. If it were an ECM issue, bypassing the relay should still kick the pump on. I’m at a loss now. Any suggestions?

 

[zora]

do you have another relay in the box with the same numbers on it. If so swap the relays to check if the FP relay is bad. Since it wont work with the 12 volts direct, the pump or the connector or the ground are bad. Where did the adaptor come from, was it part of the new pump?