I have a 99 yukon 5.7 vortec and just replaced the oil pressure sensor, distributor, plugs, wires, intake manifold gaskets, and injectors with new ac delco mpfi injectors. The truck ran fine before the work but now will not start. Sometimes it will idle but the second I touch the throttle it dies, but the majority of the time it just runs for about 5 seconds or just won't start at all.
I turn the key on, hear the fuel pump prime for a couple seconds and shut off. With a fuel gauge attached at the rail it only goes to 10-15 psi when it primes and then drops to 0 when the pump shuts off. I thought it was my fuel pump so I then replaced it with a new delphi pump and replaced the fuel filter but the issue persists.
I'm starting to lean towards the new injector assembly being bad but don't know if it would warrant such a large drop in pressure. Before I take the upper intake off I wanted to seek advice here.
I turn the key on, hear the fuel pump prime for a couple seconds and shut off. With a fuel gauge attached at the rail it only goes to 10-15 psi when it primes and then drops to 0 when the pump shuts off. I thought it was my fuel pump so I then replaced it with a new delphi pump and replaced the fuel filter but the issue persists.
I'm starting to lean towards the new injector assembly being bad but don't know if it would warrant such a large drop in pressure. Before I take the upper intake off I wanted to seek advice here.