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86 GMC 5.7 rebuilt having problems!!



Hello all,


I will start by stating that this is my frist GM vehicle and first time i have rebuilt a GM/ american engine. I've been into foreign for years and recived this truck for swaping an engine on a toyota and fixing a clutch on a hyundai. Can't complain about the price. The orginal problem with the engine was a spun rod bearing. Replaced the crank, main/rod bearings, piston rings, gaskets, etc. The engine is 60 over, yes i have the right rings. My problem is that when i start the engine it runs pretty rough and then when it warms up it will die even if its to the floor. The engine WILL NOT idle either. I am attempting to use this truck to pull my wave runners and boat and desperatly need help. Ask/ give adivce and I will try to answer all the tech questions that need answering. I'm not sure if the timing is right. I was 180 off at first but got it to fire and run. It runs like it is missing. The vacuum diagram is a bit confusing also not sure where all the valves and check valves are located and what not. ANY help will do.




Thanks in advance.

Brian :cheers:

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Check your EGR valve. See if you can force it to open. There's a chance that's the problem, as I've heard of it before. Also, is it carbureted or FI? If it's carbureted then the carb probably needs a rebuild.






egr valves can cause stalling at idle, but not at full power.


they have the same effect as having a major vacuum leak so it doesn't sound like the problem.

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