Backfiring? and i know it is not my optispark
08-20-2008, 08:51 PM
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Backfiring? and i know it is not my optispark so about 2 or 3 months ago...car was stock besides catback...i was racing a shitstang on the highway and i started to backfire near redline and bog down a little...put a cold air on, started to do it a lil worse...i knew i needed headgaskets so me and my buddy tore the car apart, threw some longtubes on, catless y pipe and bought redone LT1 heads...started to drive my car home, and it started sputtering and bogging when i wud take off...and when i get on it, it backfires real hard...and ive left the car at my buddies garage for the last few weeks because him nor anyone else can figure it out, and apparently when he puts it in the garage at night, even at idle itll backfire...not throwing any codes or anything, at one point i did and it said "electrical spark ground"...so i have no idea whats going on, someone said maybe worn out cam which will ruin me if it is because im officially broke. if you have any ideas pm me because im completly lost and i really need some help on this one 
08-20-2008, 10:30 PM
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Does it run bad as soon as you crank it up or after it runs for a while? We need a little more info on what its doing. If it started doing it all at once i believe it would be something electrical and not in the engine like a worn cam (hopefully). Bad oxygen sensors or a bad maf will make a car run very rich and backfire a lot, but the cars computer doesnt use readings from them for the first few minutes of running.
08-22-2008, 03:07 PM
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well the first time i drove it, i drove it for about 20 minutes, then it started to heat up and started to run like garbage, almost didnt make it up a long hill before my house, had to let people pass...recently ive been leaving it over night at my buddies garage, and he moves it in and out at night, and the kid that moved it the other day said that at idle it was backfiring a little bit. the thing that confuses me is that it does it at different times. for instance, ill drive around for about an hour and ill be drivin at decent rpms...i stop at a redlight and itll start doin it at like 1500 rpms
08-22-2008, 04:25 PM
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I had a very similar issue that I didn't want to believe was an opti and sure enough it was. Pull your plugs I had a few that were wet due to not firing. Also the ICM is known to cause good running conditions when cold but as the motor heats up it will begin to run poorly if it is going bad...
08-22-2008, 04:29 PM
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I had a very similar issue that I didn't want to believe was an opti and sure enough it was. Pull your plugs I had a few that were wet due to not firing. Also the ICM is known to cause good running conditions when cold but as the motor heats up it will begin to run poorly if it is going bad...
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08-22-2008, 07:09 PM
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right, it does sound like opti because ive been thru it before, but i jus changed it and it is still going on, that is why i have no idea whats goin on. i was told today at a speed shop that the fact that its a roller cam means it should be worn out with 97k. im also thinking one of my valves may be stuck? but honestly i have no idea, so im glad you guys are throwin these ideas out there because theres a couple already i didnt think of. the biggest issue is that my service engine light came on after like 15 minutes of doing it, turned my car off, and the next time i started it, the light was gone and it hasnt come back on since.
08-23-2008, 02:16 PM
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for rite now jus an OEM one cuz i need to get it goin again and i jus dumped all my money into the car, didnt plan on this happening, but im savin up my pennies for the msd
08-24-2008, 01:47 PM
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I had a very similar issue that I didn't want to believe was an opti and sure enough it was. Pull your plugs I had a few that were wet due to not firing. Also the ICM is known to cause good running conditions when cold but as the motor heats up it will begin to run poorly if it is going bad...
08-24-2008, 10:10 PM
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i was thinking ignition coil too,which is most likely the first step, but does timing make sence to anyone? i have a few people tellin me my timing is prolly all messed up. but honestly the thing making it tough is that there is a million things it could be, but most likely fuel or time related
08-25-2008, 12:19 AM
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Well, the first few things you could do would be :
- Scan it. (Im sure it threw codes at some point, they will be there)
- Swap in a coil/ICM assembly from a car you know runs fine (maybe a friend?)
- Check your fuel pressure.
If you did not touch the cam or anything when you ripped it apart, there is no way its out of timing (unless the timing chain broke).
- Scan it. (Im sure it threw codes at some point, they will be there)
- Swap in a coil/ICM assembly from a car you know runs fine (maybe a friend?)
- Check your fuel pressure.
If you did not touch the cam or anything when you ripped it apart, there is no way its out of timing (unless the timing chain broke).
08-25-2008, 07:33 AM
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i was thinking ignition coil too,which is most likely the first step, but does timing make sence to anyone? i have a few people tellin me my timing is prolly all messed up. but honestly the thing making it tough is that there is a million things it could be, but most likely fuel or time related
08-25-2008, 10:26 AM
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Take your coil to Autozone or any other place that will test it. They can do your coil and ICM for free and let you know. You should also pull your wires and ohm test them. This is the best and basically only way to truly know if the wires are in good shape.
08-27-2008, 09:08 PM
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yea i gave up on trying to do things myself, took it to a mechanic, he got me all excited calling me sayin ur cars done, he said i had a crossed wire. i started to drive it for about 2 minutes and it started again. tomorrow im going to tell him to check my ignition coil and module because that honestly sounds like it....oh yea and i left a plastic bag on my passengers seat for the last 2 weeks and the design of the bag cooked onto my seat
as if nothing else could go wrong
as if nothing else could go wrong
08-29-2008, 03:43 PM
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well apparently when my car warms up, 2 of my cylinders arent firing, so now the guy cant figure out whats causing it to do that. it threw another code saying something along the lines of fuel circuit