Check out some similar questions!

foulk78 · Dec 5, 2011, 05:17 PM

I am working on a 92 chevy truck, 5.7 TBI. It starts and runs momentarily but loses fuel after about 30 seconds. You can give it throttle and it will run... but rough. I have checked fuel pressure (9-10 psi), cleaned injectors and kitted throttle body, blew out the egr valve, disconnected coolant temp sensor, new fuel filter and checked for water in the gas. It ran fine two weeks ago and after setting for a week 1/2, this is how it is acting.

CaptainRich · Dec 6, 2011, 07:16 AM

Can you get your hands on a proper scan tool? GM Tech I scan tool?
That can reveal much about O2 sensor reading and also TPS readings.
Any codes yet?

foulk78 · Dec 17, 2011, 06:46 AM

I can get a scanner, but it would just be a generic one. Truck isn't throwing codes until right before it dies. I am just assuming that would be air/fuel mixture fault since it happens when the fuel stops at the injectors. Catalytic converter?

CaptainRich · Dec 17, 2011, 06:59 AM

A generic scanner could work if you can monitor data.
Not likely the converter: symptoms don't match a clogged converter.
Is the fuel pressure being monitored during the stall event? Can you judge fuel volume? There may be sufficient pressure but even with a new filter, the pump cannot deliver sufficient fuel volume.
Another thing to watch would be a noid light connected immediately when the stall occures. If the noid light is still flashing, you can be fairly certain the fault isn't the Engine Control Module (ECM).

TxGreaseMonkey · Dec 17, 2011, 07:02 AM

I suspect a failing Ignition Control Module (ICM).

foulk78 · Dec 18, 2011, 04:49 AM

Fuel pressure stayed consistent even after it died. As far as volume, there seems to be a sufficient spray at the injectors. There is even a heavy fuel smell from the exhaust (not the "rotten egg" O2 sensor smell). I will get my hands on the scanner and see what I can find out. I didn't think catalytic converter either, but that was suggested to me. Leaning heavily towards the TPS.

TxGreaseMonkey · Dec 18, 2011, 05:22 AM

90%+ of all crank but won't start problems are electrical related, not fuel. Since your truck's exhaust wreaks of fuel (flooded), I would focus on the ignition system. My bet is your old ICM is not firing when the ECM wants it to; hence, it won't stay running. Super simple 10-minute job ($47). If you keep trying to start the truck with a bad ICM, you could blow the exhaust system off if a random spark ignites the fuel build-up in the converter. I'll eat my sombrero, if it's the TPS.