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1996 3.1L running funny after rebuild


gregp08
01-10-2008, 10:53 PM
Hey guys, my name is Greg, and I just joined these forums because as most of yall i got a lumina. 3.1 96 to be exact. Anyway, my friend and I did a lil project lately because my head gasket blew.

We took the engine apart to replace the gaskets, so, we replaced all of em. At the same time, my dad(not knowing much about cars) took the old heads to a mechanic and they decided to sell him some new heads. They looked good and all, so my friend and I put everything together. We also put new spark plugs as well as new wiring for em. the car started up ran all good and clean. we took it on the highway and it overheated on us. also, we found that the coolant was being occupied by gas, because it smelled like it. we decided to head back to the books, and we discovered that we made a mistake while bolting down the new headbolts that we bought for the new heads. we didnt go the extra 90 degrees. so, i took off the valve covers and tightened down the heads, and repalced the oil and coolant for the second time within lke 2 weeks. total overall ive spent around a grand on all these upgrades.

We started it up and it still ran bad. check engine said random/multiple cilinder misfire. the engine sounded real unstable. so since the coil packs were original, we replaced them. nothing. the engine is still running unstable. any advice to what it could be?

16th hippy
01-11-2008, 01:48 AM
worst case scenario, you warped the brand new heads. at this point, at a minimum, you will need to replace the head gaskets. since the 90deg after torque was not done, and it "overheated", the gaskets are useless. since you are gonna have the heads off anyway, get a good straight edge and feeler gauges to check heads for warpage. make sure to get new head bolts again if this is the case. now, there are a few things to check, and pray that luck is on your side. coil packs replaced, but what about spark plugs and wires when heads were redone? pull the plugs now and see how they look. if coolant got into the cylinders it could have fouled the plugs. if they look bad, replace them. it is far cheaper and easier to do this than re-doing heads and so on. check for vacuum leaks too. you could just have some injector o-rings pinched somewhere(an example, but vacuum leak could be anywhere.) I am sorry if i am deliverig bad news, but i won't sugar coat it. hope you are lucky. let us know how it's going/

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