The vehicle is a 1994 K1500 suburban with the 5.7L gas V8. I have changed the fuel pump (12-13 psi), fuel filter, checked the fuel return line, changed the idle air control valve, manifold air pressure sensor, checked/changed all vacuum lines, checked the voltage to the ecm and it was constant 12v on both sides of the fuseable link and the same at the ecm but i changed the ecm anyway, EGR moves as described in the shop manual... no change. when the engine is cold it starts and runs fine until it warms up then stalls (3-5 minutes). After the engine is warm and it stalls it will restart immediately without even turning the ignition switch off (with all lights on the dash remaining on) and run for 30-45 seconds and then shudder and stall. Interestingly the only way it will continue running is if I block plug the manifold air line from the TBI but of course that produces the appropriate error code but unless I'm doing a sensor voltage test there have never been any fault codes since it started doing this about 3 weeks ago. Where do I go next with the troubleshooting?
Not near enough fuel pump pressure,should be 45 lbs
if I remember correctly,9-13 psi is for a carburated ingine,and a manual pump on the side of the engine,I remember on the 95 4.3 engines gm had a 45lb.pump and a 60lb pump,pull the air breather ring off the throttle body and have someone cycle the key while your looking down in the throttle body,it should spray a mist in a circular pattern inside the throat
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Wrong answer, The GM manual says 9-13 PSI for the 1994 TBI system (it's a throttle body). Later model Multiport systems have the higher pressure. Any ideas on where to go next?
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