Odd Misfire Problem with LS2
04-05-2006, 04:51 PM
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Odd Misfire Problem with LS2 Hey guys I got wierd one for you. 402 LS2 in a 2003 C5. Pump gas, AFR 225's, 234/234/115 Comp XE-R, 60lb Motrons, NGK TR6 (0.045), JP dual roller chain.
Runs great part throttle and idle. When going WOT at about 3200 rpms, it misfires and stumbles. Air fuel does not move from 12.6 and timing is 22 degrees.
Changed the obvious plugs and wires. At this point I'm at a loss. My next plan is to change the crank and cam sensors but I don't think that's it since they are not setting codes of any sort. I also verified good ground connections.
Has anyone had any problem with the JP chains? This is only the second time I'm using it. The first one worked fine.
Mikey
Runs great part throttle and idle. When going WOT at about 3200 rpms, it misfires and stumbles. Air fuel does not move from 12.6 and timing is 22 degrees.
Changed the obvious plugs and wires. At this point I'm at a loss. My next plan is to change the crank and cam sensors but I don't think that's it since they are not setting codes of any sort. I also verified good ground connections.
Has anyone had any problem with the JP chains? This is only the second time I'm using it. The first one worked fine.
Mikey
04-05-2006, 05:28 PM
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Yes, it's the new JP LS2 chain. I can watch the low-high and high-low counts and they do not seem to be affected when the misfire occurs. No cam postion codes either. It's a wierd one.
04-06-2006, 10:42 AM
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Originally Posted by oange ss
his afr would spike lean if that were the case
04-06-2006, 10:01 PM
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I'm also experiencing a weird problem with my new LS2 setup. Sometimes between 5000-6000 rpm the motor will misfire/bog for a short period of time. It is a random issue. My 1st outing at the track a few week back it occured everytime in 2nd & 3rd gears (3 passes). On the drive home, I couldn't repeat it. My setup is a low comp (8.4:1) LS2 that I plan to install a turbo on later this year.
My AFR is rock steady at 12.8:1 (WB in the car). I'm running 42 lb/hr injectors, 255 lph pump, and the duty cycle is 65-67%. I'm confident I'm not having a fuel issue. I've changed plug wires and plugs (twice: TR5 @ 0.040" & 0.035"). No change. No PCM codes (thought it might be a crank or cam position sensor). I've check everything I can think of twice (the above, grounds, other sensors, etc...). When this occurs there is nothing out of the ordinary I can pull out of my HP Tuners logs. This one has got me stumped.
Curiously looking for any thoughts.
My AFR is rock steady at 12.8:1 (WB in the car). I'm running 42 lb/hr injectors, 255 lph pump, and the duty cycle is 65-67%. I'm confident I'm not having a fuel issue. I've changed plug wires and plugs (twice: TR5 @ 0.040" & 0.035"). No change. No PCM codes (thought it might be a crank or cam position sensor). I've check everything I can think of twice (the above, grounds, other sensors, etc...). When this occurs there is nothing out of the ordinary I can pull out of my HP Tuners logs. This one has got me stumped.
Curiously looking for any thoughts.
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04-07-2006, 05:32 AM
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Originally Posted by ozws6
I'm also experiencing a weird problem with my new LS2 setup. Sometimes between 5000-6000 rpm the motor will misfire/bog for a short period of time. It is a random issue. My 1st outing at the track a few week back it occured everytime in 2nd & 3rd gears (3 passes). On the drive home, I couldn't repeat it. My setup is a low comp (8.4:1) LS2 that I plan to install a turbo on later this year.
My AFR is rock steady at 12.8:1 (WB in the car). I'm running 42 lb/hr injectors, 255 lph pump, and the duty cycle is 65-67%. I'm confident I'm not having a fuel issue. I've changed plug wires and plugs (twice: TR5 @ 0.040" & 0.035"). No change. No PCM codes (thought it might be a crank or cam position sensor). I've check everything I can think of twice (the above, grounds, other sensors, etc...). When this occurs there is nothing out of the ordinary I can pull out of my HP Tuners logs. This one has got me stumped.
Curiously looking for any thoughts.
My AFR is rock steady at 12.8:1 (WB in the car). I'm running 42 lb/hr injectors, 255 lph pump, and the duty cycle is 65-67%. I'm confident I'm not having a fuel issue. I've changed plug wires and plugs (twice: TR5 @ 0.040" & 0.035"). No change. No PCM codes (thought it might be a crank or cam position sensor). I've check everything I can think of twice (the above, grounds, other sensors, etc...). When this occurs there is nothing out of the ordinary I can pull out of my HP Tuners logs. This one has got me stumped.
Curiously looking for any thoughts.
Try both cam and crank sensors. I did not see anything out of the ordinary in my logs either.
Mike
04-07-2006, 07:10 AM
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Originally Posted by mikey
Well guys, it's fixed. Wound up being a defective cam position sensor. Brand new one too. Go figure.
Mikey
Mikey
04-10-2006, 07:24 AM
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Originally Posted by ozws6
Mikey, Thanks for the help! I changed my cam and crank position sensors today and my stumble problem is gone!
