HELP HELP HELP anybody, i hate this lt1 :bang:
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Teching In
Joined: Sep 2008
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From: Dfw Texas
HELP HELP HELP anybody, i hate this lt1 :bang: Hey guys I REALLY NEED THE HELP, ive tried alot to fix this thing, im so frustrated i almost swore off fbodies, so heres details on what ive done.
Man i seriously need any info i can get, heres the low down, i bought a 96 z28 almost a year ago and the first 6 months it was the best car ive ever driven, ran strong and never quit. The last 6 months of that year are another story. Ive had a p1300 code thrown, got that fixed, went through 4 optisparks (all ac delco) never got them wet but they just seem to quit. wire harness broke down and had to replace that. Had oil leaks break out everywhere so replaced EVERY seal. Then had a major misfire problem in my number one cylinder. Thanks to orileys went through 3 power steering pumps and 2 ac clutches (none where good for more than a day thanks to the factory screw up). Any way i just cant seem to fix the misfire, i grounded out my spark plug and checked it it fired everytime, my coil was good, my spark plug was unscathed, but new wires and o2 sensors on it almost monthly, my springs and valves where amazingly clean, and i put in a new injector and i checked its pulses, everything was great. STILL A MISSFIRE. it just gets steadily worse. My cats then clogged up and i had to replace them hoping that might be a culprit BUT STILL MISSFIRING BAD, we put it on a dyno with diagnostic equipment and my number one cylinder is dead across the board, but i still have compression in the 160s, i sea foamed it, and the stupidest part it only has 94k miles, now im stuck, spent alot of money and sadly i dont even rag this car it just flat hates its life. Just need some advice guys? besides ls1 time. thats coming.
Man i seriously need any info i can get, heres the low down, i bought a 96 z28 almost a year ago and the first 6 months it was the best car ive ever driven, ran strong and never quit. The last 6 months of that year are another story. Ive had a p1300 code thrown, got that fixed, went through 4 optisparks (all ac delco) never got them wet but they just seem to quit. wire harness broke down and had to replace that. Had oil leaks break out everywhere so replaced EVERY seal. Then had a major misfire problem in my number one cylinder. Thanks to orileys went through 3 power steering pumps and 2 ac clutches (none where good for more than a day thanks to the factory screw up). Any way i just cant seem to fix the misfire, i grounded out my spark plug and checked it it fired everytime, my coil was good, my spark plug was unscathed, but new wires and o2 sensors on it almost monthly, my springs and valves where amazingly clean, and i put in a new injector and i checked its pulses, everything was great. STILL A MISSFIRE. it just gets steadily worse. My cats then clogged up and i had to replace them hoping that might be a culprit BUT STILL MISSFIRING BAD, we put it on a dyno with diagnostic equipment and my number one cylinder is dead across the board, but i still have compression in the 160s, i sea foamed it, and the stupidest part it only has 94k miles, now im stuck, spent alot of money and sadly i dont even rag this car it just flat hates its life. Just need some advice guys? besides ls1 time. thats coming.
Thread Starter
Teching In
Joined: Sep 2008
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From: Dfw Texas
Also forgot to add, its very irradict. There are rare in a blue moon days it drives just fine, then theres days it kills itself, and the days it just runs like ****. also yes i have a good fuel pump.
That compression seems a bit low, typical compression for an LT1 should be in the 170-180 area as far as I know.
I am either going to say compression, or the injector on that cylinder. But since you already took care of the injector I would be double checking the compression on ALL cylinders. Report back with what you get for numbers.
I am either going to say compression, or the injector on that cylinder. But since you already took care of the injector I would be double checking the compression on ALL cylinders. Report back with what you get for numbers.
If you have fuel and spark to the cylinder, the only thing I could think of is possibly something wrong with the valvetrain on #1 (Rockers not properly adjusted or messed up). Maybe you could check the valves to ensure they are opening and closing properly. If that's not it, I'm out of ideas.
Thread Starter
Teching In
Joined: Sep 2008
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From: Dfw Texas
Im going to double check the compression all the way around and see what i get in comparisson. As weird as this this is being ive really started to wonder if my computer might be bad or going out.
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It is possible, but you want to make sure everything is mechanically sound before you go blaming the PCM. Checking your compression on all cylinders will give you a GOOD idea as to whats going on.
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From: Decatur, TN (N-W of Athens)
You said the coil was good, but did you replace/test the spark control module? (Also called ICM for Iginition Control Module). If by some chance you don't know where it is, its behind the coil. While you have it off, throw like 5-6 washers behind it, so it's spaced out from the head. It's a 'ICM' mod, which keeps it cooler. Electricals don't like heat, and having it ON the head has MUCH heat lol Not sure why GM did that :\ A small bit of plastic tube would work better than washers too, less to transfer heat (PVC recommended).
On The Tree
Joined: Jul 2005
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From: Gilbert, AZ
Sorry to hear you're having problems with the car. There are times when the problems you're encountering need to be taken on by someone whose automotive repair skill level is a notch above yours, and this sounds like it just might be the case. Check around here to see if someone can recommend a mechanic/shop in your area who is well-versed with LT1's. Good luck sir.
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From: Decatur, TN (N-W of Athens)
Holy spelling bee preliminaries Batman...
Sorry to hear you're having problems with the car. There are times when the problems you're encountering need to be taken on by someone whose automotive repair skill level is a notch above yours, and this sounds like it just might be the case. Check around here to see if someone can recommend a mechanic/shop in your area who is well-versed with LT1's. Good luck sir.
Sorry to hear you're having problems with the car. There are times when the problems you're encountering need to be taken on by someone whose automotive repair skill level is a notch above yours, and this sounds like it just might be the case. Check around here to see if someone can recommend a mechanic/shop in your area who is well-versed with LT1's. Good luck sir.
If you have fuel and spark to the cylinder, the only thing I could think of is possibly something wrong with the valvetrain on #1 (Rockers not properly adjusted or messed up). Maybe you could check the valves to ensure they are opening and closing properly. If that's not it, I'm out of ideas.
Thread Starter
Teching In
Joined: Sep 2008
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From: Dfw Texas
Hey guys i appreciate the help, Ive checked all over ls1 tech for similar issues and solutions and now I'm just left with having to make a thread. I'm going to check the compression this weekend. Also i have put a new ICU above the coil with the proper gels and everything. I have not checked for a cracked head or anything along those lines but the car does not show any signs like fouled plugs or coolant leaking in the block, also it is burning clean, no visible smoke out the back and yes i have said this is above me and taken the car to several performance shops in the dfw area and still no one can tell me exactly whats going on, just alot of guessing and naming off things Ive already done.
Thread Starter
Teching In
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From: Dfw Texas
there is a silicon type gel that is suppose to be lightly applied to the back of the icm against the metal plate of the bracket to help ground it out and prevent surges and such through the metal since it is so close to the coil, also it acts as an insulator. If you buy a new icm it should come with a pack a gel for it.
there is a silicon type gel that is suppose to be lightly applied to the back of the icm against the metal plate of the bracket to help ground it out and prevent surges and such through the metal since it is so close to the coil, also it acts as an insulator. If you buy a new icm it should come with a pack a gel for it.
that doesnt mean anything it could be blown inbetween the cylidners or it could be cracked inbetween the cylinders...you have to do your compression check without your plugs...check your compression with no plugs in the block at all....see what you get...also a blown head gasket wont always show a smoke blowing out the back...are you positive its number one cylinder with no compression?? have you actually physically watched the pushrods working the valves with bumping the motor?? you could have a cam that is trashed...you could also have a collapsed lifter. or a bad push rod... it could be a rocker arm that is not pivoting, or siezed or even worn..
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From: Decatur, TN (N-W of Athens)
there is a silicon type gel that is suppose to be lightly applied to the back of the icm against the metal plate of the bracket to help ground it out and prevent surges and such through the metal since it is so close to the coil, also it acts as an insulator. If you buy a new icm it should come with a pack a gel for it.