LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Whats an out of balance engine feel/sound like?

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Old Aug 25, 2003 | 11:28 PM
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Whats an out of balance engine feel/sound like?

Im having a problem trying to find a miss/dead spot in my newly assembled engine. I have put all new injectors and sparkplugs in. The plugwires were replaced about 1k ago and none seem to be abnormal looking. I tried to keep the motor running and pull off each spark plug individually and they all seemed to make a difference in the way it ran. I checked all the valves for adjustment and they seemed to check out fine. So now im kinda wondering wtf is wrong with it. If a motor is out of balance would it have the same syptoms as a missfire? But then i don't think that id notice it all the way down at an idle (that it won't really keep anyway).

Im just all out of ideas...im thinking that maybe the opti is bad? I know that even before I pulled this motor apart that it idled irregularly but it was nothing like this. (car also has new MAF, 02s, fuel pump/filter, IAC, ie pretty much everything electronic is new except for the opti, and tuning for the 32lb injectors and other mods)

I thought you guys could throw out a few ideas as i don't think it is an unbalanced motor situation, i thought maybe some of you who have had opti problems could tell me if this is what it was like when yours went bad?
Old Aug 26, 2003 | 04:28 AM
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ttt
Old Aug 26, 2003 | 10:00 AM
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Old Aug 26, 2003 | 10:57 AM
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What MSD unit are you running? How about the coil? Sounds like an ignition problem to me.
Old Aug 26, 2003 | 11:27 AM
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Well to try and eliminate the problem I removed the digital 6 and I am just running the blaster HVC coil right now (it ran the same both with and without the dig. 6). The coil does say "for msd 6 series ignitions only" Could it be a coil problem if it is just running rough? I figured a coil would either make it run or not run. Ive thought about maybe the ignition control module may be bad? (that module right next to the coil)
Old Aug 26, 2003 | 11:41 AM
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Well, try replacing the coil with the stocker. No engine trouble codes either? I guess you'll have to take it to a shop and see if they can find the problem. I am sure you will find the problem sooner or later, don't get discouraged.
Old Aug 26, 2003 | 11:45 AM
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Ill have to swap the coil out and try that....otherwise im thinking the ICM or the opti??
Old Aug 26, 2003 | 02:18 PM
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Does anyone else have any ideas? I really don't want to replace a $200 distributor and $65 ICM if its not going to do anything,
Dan
Old Aug 26, 2003 | 09:41 PM
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Dood if your worried about a few hundred dollars, your driving the wrong car!
Old Aug 26, 2003 | 09:56 PM
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Does it run rough all the time? If you can get your car to idle as slow as you can when warm and spray a mist of water on your spark plug boots at the plug one at a time if you have any bad wires boots or connections you will see it arc. Just because plug wires look goood that doesn't mean they are. Did you check the resistance in each wire? A bad ground anywhere can also cause a miss. A vacuum leak can also cause a miss. I could go on & on You need to eliminate 1 thing at a time and you will probably find it.
Old Aug 27, 2003 | 12:07 AM
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Originally posted by EDS Z28
Dood if your worried about a few hundred dollars, your driving the wrong car!
Youre right a few hundred dollars is not too much when looking at this project but a hundred here and a hundred there ADDS UP FAST. Ive got 13k in performance/replacement parts as it as...and i can assure you the time slips will not be 13k impressive.




But yeah i need to start checking for things one at a time but my only problem is that it won't run by itself, when it gets down to an idle it just dies. I need pull the wires back off and check them out for resistance and check vaccuum leaks too. Thanks for ideas.....
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