This is driving me nuts. 2005 lQ9 coming off fresh rebuild. Engine will run great until I turn on the fuel pump, then floods out. It ran fine previously. Same computer ,same harness.Previously,Ran fine with mass airflow not connected. Running aftermarket harness.
only code thrown is PO102. Swapped fuel pumps. Swapped computers with one that runs fine in another car. Swapped mass airflow from other car. Checked injectors for volts. Made sure everything is grounded.
Nothing changed makes any difference. Won’t start with fuel pump on. Fires right up when we turn it off. Then runs fine till we turn the pump on ( or we finally run out of gas in the rails.) 58 PEI from pump ( factory 2007 Silverado pump)
Any ideas would be greatly appreciated