well as some of ya'll probably know my engine fried here a while back and had to be completely rebuilt cylinders where bored over and the cam line bored out and a helix cam installed, a super B single turbo was also installed and new 4in exhuast from turbo back. All this done by a shop as truck was under warranty. I went to pick up my truck today and he had some good news and bad news. Good news everything back in and it cranks and runs bad news is when it was all back together yesterday they cranked it up and let it sit and idle after 30 minutes or so the engine just started running away like someone geting on the pedal and back off again. they killed the engine and started trouble shooting. after finding nuthing they switched out the ECM with one from another truck and it didn't do it again. question here is it possible that the ECM would cuase this to happen or could it be the VP would like to spend the money the right way instead of just replaceing parts. no codes where set other then VIN doesn't match becuase of the different ECM. also they are thinking that when the journal that had to be bored and bearing installed for the call was right where the ECM is. is it possible that the heat fried the ECM. thanks

 

since they swapped the ecm and it ran fine I would say its the ecm. Your right the heat could have caused something inside to melt. Did they let it run for another 30mins with the replacement? If so and it was fine then its the ecm.

 

have them hook up a computer to the truck and look and see if the tps is moving up and down with the motor speed it could be the apps going out or shorting.
take it for a drive with the other ecm and see if it clears up

 

he said with the ECM swapped out and with the one from different VIN in it makes it run rough for a min or two but then clears up. they put a snap-on scan tool on it but don't know if that will show it. just trying to hit it with the first shot to keep the $$$ down. thanks for all the imput.

 

I would drive it with the old ecm,The obd2 needs to learn the truck over again.Letting it sit and idle does nothing for it.Then if it doesnt clear up,then go for there.May be it will set a code and then you will know what you need to do.I have seen this before.