Idle problem...missfires
10-19-2008, 05:49 PM
#1
Senior Member
Thread Starter
Idle problem...missfires
Ok I need some help here, kinda lost. I have some ideas on where to go but id like some more opinions on the matter.
MODS
42lb injectors
2.9 PUlley
GM Stage 2 Tune
AEM Dry flow airfilter
Ported and Polished Internally Lower intake manifold
Dual Pass with Option B
Last week my car started having idle problems at startup. When i start the car the idle is horrible. Its very rough, bouncing from like 500RPMS to 1800 RPMS. Giving it gas can smooth the revs out if i hold it. As soon as i let go of the case the idle starts to bounce around again. If i drive the car its really jerky for a few minutes, then the idle problems go away and the car drives normally. If i come to a stop IDLE will sit perfectly and never have a problem again. If i turn the car off and then turn it back on, even if only turning it off for a second, upon startup the idle problems will be back, but not as bad as a cold start. And again driving the car or letting it idle, eventually the idle problems go away. They go away faster if you drive it.
Now today i checked the plugs and they appear to be fine, they are new plugs that are maybe 1 month old. Gapped at .35. I hooked HPTuners up to the car and its showing missfires on all 4 cylinders, alot of missfires too. #1 cylinder seems to missfire the most, but they are all missfiring pretty bad. For good measure i took the supercharger and everything apart and double checked all the connections and made sure everything was tight. We also reflashed the Tune for good measure. I have taken the battery cables off to let the PCM relearn. I dont think its a problem with the intake manifold because I have been driving around with that for almost 2 months with no problems. I have an HPTuners log that my buddy will hopefully post up for me because its on his laptop.
Now i have had this problem in the past, pretty much the exact same thing that even threw a missfire code. In the past what i did was throw some fuel injector cleaner in the tank, change the plugs and the problem would be gone for like 6 months. Its happened to me twice now. But this time fuel injector cleaner doesnt appear to be fixing the problem and the plugs are pretty much brand new.
Heres what i plan on doing tomorrow.
-Put in my stock 36 lb injectors and stock tune
-Replace the fuel filter
-Try a different coil pack
Now one other thing, about 2 weeks ago i was working on my car and didnt put the screws to the fuel rail back in, i took it for a drive and hit boost, got a check engine light, quickly pulled over and 2 of the injectors had been pushed out of the engine. Towed the car home, let the gas evaporate, put everything back together and the car ran fine. The injectors that got pushed out were on the 2 left cylinders when looking at the car from the front, so i think 3&4.
So right now im thinking its either and electrical issue or a fuel issue, but im not sure which. I dont really think its a blown engine or anything else because like i said, the car runs 100% fine after a minute or two of driving. No knocks, no burning oil, no white smoke, but there are CELS.
The first CEL i have always had since i put my injectors and stage 2 tune, it comes and goes, this is Bank 1 Oxygen Sensor too rich.
P0172 - Bank1 Oxygen Sensory Rich
P0300 - Random Missfire Detected
P0101 - MAF Input too high/low - This one might be old, didnt see the date but i had this one before when i was playing with a ported throttle body.
Now after having cleared the codes, the only one to come back is mulitple missfires detected.
So any suggestions?
MODS
42lb injectors
2.9 PUlley
GM Stage 2 Tune
AEM Dry flow airfilter
Ported and Polished Internally Lower intake manifold
Dual Pass with Option B
Last week my car started having idle problems at startup. When i start the car the idle is horrible. Its very rough, bouncing from like 500RPMS to 1800 RPMS. Giving it gas can smooth the revs out if i hold it. As soon as i let go of the case the idle starts to bounce around again. If i drive the car its really jerky for a few minutes, then the idle problems go away and the car drives normally. If i come to a stop IDLE will sit perfectly and never have a problem again. If i turn the car off and then turn it back on, even if only turning it off for a second, upon startup the idle problems will be back, but not as bad as a cold start. And again driving the car or letting it idle, eventually the idle problems go away. They go away faster if you drive it.
Now today i checked the plugs and they appear to be fine, they are new plugs that are maybe 1 month old. Gapped at .35. I hooked HPTuners up to the car and its showing missfires on all 4 cylinders, alot of missfires too. #1 cylinder seems to missfire the most, but they are all missfiring pretty bad. For good measure i took the supercharger and everything apart and double checked all the connections and made sure everything was tight. We also reflashed the Tune for good measure. I have taken the battery cables off to let the PCM relearn. I dont think its a problem with the intake manifold because I have been driving around with that for almost 2 months with no problems. I have an HPTuners log that my buddy will hopefully post up for me because its on his laptop.
Now i have had this problem in the past, pretty much the exact same thing that even threw a missfire code. In the past what i did was throw some fuel injector cleaner in the tank, change the plugs and the problem would be gone for like 6 months. Its happened to me twice now. But this time fuel injector cleaner doesnt appear to be fixing the problem and the plugs are pretty much brand new.
Heres what i plan on doing tomorrow.
-Put in my stock 36 lb injectors and stock tune
-Replace the fuel filter
-Try a different coil pack
Now one other thing, about 2 weeks ago i was working on my car and didnt put the screws to the fuel rail back in, i took it for a drive and hit boost, got a check engine light, quickly pulled over and 2 of the injectors had been pushed out of the engine. Towed the car home, let the gas evaporate, put everything back together and the car ran fine. The injectors that got pushed out were on the 2 left cylinders when looking at the car from the front, so i think 3&4.
So right now im thinking its either and electrical issue or a fuel issue, but im not sure which. I dont really think its a blown engine or anything else because like i said, the car runs 100% fine after a minute or two of driving. No knocks, no burning oil, no white smoke, but there are CELS.
The first CEL i have always had since i put my injectors and stage 2 tune, it comes and goes, this is Bank 1 Oxygen Sensor too rich.
P0172 - Bank1 Oxygen Sensory Rich
P0300 - Random Missfire Detected
P0101 - MAF Input too high/low - This one might be old, didnt see the date but i had this one before when i was playing with a ported throttle body.
Now after having cleared the codes, the only one to come back is mulitple missfires detected.
So any suggestions?
Last edited by -Jayson-; 10-19-2008 at 06:18 PM.
10-25-2008, 04:34 PM
#3
10-26-2008, 09:52 AM
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well first off you have a problem with your tune, im going to take a guess and say your tune rich lol. Also you might have an issue with your maf. I would take it out and clean it as well as possible. While doing this, for the hell of it, also clean your throttle body. If you want to know why, in short, carbon builds up makes the idle rough, so clean it. For the random misfire detected, change your plugs to bkr7e's. Hopefully this helps.
As far to the above person asking about rain, im assuming you had an issue with rain/humidity? That would be a problem with your maf sensor
As far to the above person asking about rain, im assuming you had an issue with rain/humidity? That would be a problem with your maf sensor
10-26-2008, 11:22 AM
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Glad you got the issue worked out I knew I was right =D. Thanks for the kind word Tom =D. I am reading up all I can about tuning etc and trying to gain as much knowledge as possible.
10-26-2008, 12:20 PM
#10
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i had bkr7es in my car, changed them to double platnums. i noticed when i took out the boot from the coilpack there was like dirt/black dush all around the outside of the boot like the last plug wasnt sealed properly or something. but i changed all the plugs last night, new 02 sensor in the header, and now im just waiting to see if the cel goes out.
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