Hey guys. Need some advice on diagnosing a motor problem on my tow pig. 1992 K2500 suburban with the 7.4l 454 big block. Truck has been a perfect truck for a long time. Started it up the other day and it cranked right up but immediately died. Never happened b4. Cranked it again and it was sputtering a bit. Drive it about a mile and damn thing is sputtering and has no throttle response once it reached operating temp. Black smoke coming out of tail pipe and was back firing. Only way I could get it to start againwas holding the pedal to the floor. Could smell it was running very rich. Limped it home and parked it for the day. Pulled all the plugs and all but three were fouled out. Had carbon globs on the tips. Changed to new plugs, wires, rotor button, distributor cap, and pvc valve. Cranked it up and she was purring so sweet. Thought it was fixed. Just let it sit and idle and once it warmed up, the motor reves up to about 2000 by itself and the injectors were dumping tons of fuel (TBI). Exhaust was light white/grey and was very strong of unburnt fuel smell. Hit the gas and it sputters and cut off. So I'm thinking coolant temp sensor. Replaced both sensors, one on drivers and other on passenger head. Filled up with coolant and fired it up. Same results as b4.
What do I need to check or change out? What is causing extra fuel to be dumped into the motor once it reaches operating temp?
Any help or even smart ass suggestions such as buy a Ford would be appreciated. Thanks John
What do I need to check or change out? What is causing extra fuel to be dumped into the motor once it reaches operating temp?
Any help or even smart ass suggestions such as buy a Ford would be appreciated. Thanks John