How much PSI should the fuel pump be pushing out on an LT1? I want to diagnose my mysterious starting problem. I searched and got 50psi and 24gph is that right?

 

1) Per the FSM 41 to 47 PSI engine idling, vacuum line to regulator disconnected. (pump pressure test)
2) With vacuum line connected pressure should drop 3-10 PSI from that noted in step 1. (regulator function test)
3) At WOT under full load, pressure should hold 41 to 47 PSI. (fuel delivery test)

 

Thank you very much. How about when the fuel pump is priming the engine before startup?

 

The pump primes the system when the ignition key is in the ON position. If the engine does not start within 2 seconds the PCM turns the pump OFF. In a properly working system the fuel pressure will hold with the engine off for several hours.

 

Ok cause i think the reason my car won't start is because of the fuel pump not holding pressure. If i try to start it, it just tries to turn over but cant. So i pump the gas while trying to turn it over still nothing. Do that again, still nothing. Try to turn it over for a 3rd time, and just hit the gas once and it fires right up. It drives normal other than a bogging at low rpms. I'm just trying to eliminate all possibilities. And yes the check engine light is on.

 

First of all the car is fuel injected so pumping the gas pedal accomplishes nothing except to confuse the PCM. By you turning the key ON & OFF several times forces the pump to prime for a longer time and get the fuel pressure up. Before blaming the pump, you may want to check for a leaky injector, as the symptoms are similar.

 

that was going to be my next guess as to what the problem could be.