I have a gen 3 5.3, btr cetrifugal cam, walbro intake pump, aftermarket rails, aftermarket regulator, 60lb deka injectors, dbw ecm tuned and vats removed by PSI, reworked harness. Got ready to fire for the first time, jumped the fuel pump to purge lines and set pressure, but when I tried to start it halfway ran for a second then died. Fuel pump primes with key on but wont start, but will start with starting fluid then dies. Heres where it gets weird, changed injectors to a fresh set of cleaned and flow tested injectors and was testing with a noid light, when I pull the fuel pump fuse it fires right up and runs until out of fuel. I put the fuse back in and no fire, prime the system and pull the fuse, starts right up and runs until its out of fuel. I even tried starting with the fuse out, then putting it back in when its running, but dies as soon as the fuse is in. Started with FP at 58psi and have tried a few lower and higher pressures, no change. Any thoughts?

 

Time to revisit the "reworked" areas of the harness.