Pontiac Repair: 91 firebird 5.7l wont start?, noid light, mpfi

Question
we replaces fuel relay, low idle, fuel pressure, map sensor, fuel filter, etc. the car has spark at plugs, has fule in rail. when it DOES start and when i aply throttle it dies. but it doesnt want to start after that. the fuel pump does kick on and off when ignition is turned on. what can be causing it not to start after that?

eric

Answer
Hi Eric:

what engine is in this a MPFI or TBI engine? it makes a difference in the fule pressure readings the MPFI the pressure should be around 40 PSI the TBI engine around 10. if the pressure are not where the need to be the car will not run. I would start there. what happened to this did it just not start 1 day or did it die going down the road and not restart? doe it have injector pulse? you need a noid light to check for injector pulse when your cranking the car. DO NOT USE A TEST LIGHT that is a good way to damage the engine computer. you should have pulse on both if it's a TBI engine and all 8 if it's MPI. start there.
Good luck :)