LS2 Backfire issue
Thread Starter
Teching In
Joined: Sep 2009
Posts: 5
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LS2 Backfire issue I'm still learning (newbie) about LS engine technology and experiencing the following:
When I let off the accelerator and coming to a stop, around 1800-1500 rpm, I can hear popping/backfire through the exhaust.
My setup is 2006 LS2 Corvette crate motor in 67 Corvette. MAF sensor is stock GM, has FAST wiring harness with GM ECM that has been modified to ignore rear O2 sensors are they were not installed. I running dual exhaust through turbo mufflers and the intake has simple 90 degree tube with K&N cone filter inside engine compartment. It is 5 speed Tremec TKO 600.
Reading through forum, that maybe H-pipe might help the issue? Or shoudl rear O2 sensors be installed?
I'm not showing any codes and driveability/performance is good as we did side by side test with another LS2 equipped C2 Corvette.
Thanks in advance for the help!
When I let off the accelerator and coming to a stop, around 1800-1500 rpm, I can hear popping/backfire through the exhaust.
My setup is 2006 LS2 Corvette crate motor in 67 Corvette. MAF sensor is stock GM, has FAST wiring harness with GM ECM that has been modified to ignore rear O2 sensors are they were not installed. I running dual exhaust through turbo mufflers and the intake has simple 90 degree tube with K&N cone filter inside engine compartment. It is 5 speed Tremec TKO 600.
Reading through forum, that maybe H-pipe might help the issue? Or shoudl rear O2 sensors be installed?
I'm not showing any codes and driveability/performance is good as we did side by side test with another LS2 equipped C2 Corvette.
Thanks in advance for the help!
I'm still learning (newbie) about LS engine technology and experiencing the following:
When I let off the accelerator and coming to a stop, around 1800-1500 rpm, I can hear popping/backfire through the exhaust.
My setup is 2006 LS2 Corvette crate motor in 67 Corvette. MAF sensor is stock GM, has FAST wiring harness with GM ECM that has been modified to ignore rear O2 sensors are they were not installed. I running dual exhaust through turbo mufflers and the intake has simple 90 degree tube with K&N cone filter inside engine compartment. It is 5 speed Tremec TKO 600.
Reading through forum, that maybe H-pipe might help the issue? Or shoudl rear O2 sensors be installed?
I'm not showing any codes and driveability/performance is good as we did side by side test with another LS2 equipped C2 Corvette.
Thanks in advance for the help!
When I let off the accelerator and coming to a stop, around 1800-1500 rpm, I can hear popping/backfire through the exhaust.
My setup is 2006 LS2 Corvette crate motor in 67 Corvette. MAF sensor is stock GM, has FAST wiring harness with GM ECM that has been modified to ignore rear O2 sensors are they were not installed. I running dual exhaust through turbo mufflers and the intake has simple 90 degree tube with K&N cone filter inside engine compartment. It is 5 speed Tremec TKO 600.
Reading through forum, that maybe H-pipe might help the issue? Or shoudl rear O2 sensors be installed?
I'm not showing any codes and driveability/performance is good as we did side by side test with another LS2 equipped C2 Corvette.
Thanks in advance for the help!
Rear O2s are not necessary, as they do nothing to adjust the fueling. All they do is tell the ECM whether or not your cats are working, and since they're tuned out, it won't hurt anything.
Thread Starter
Teching In
Joined: Sep 2009
Posts: 5
Likes: 0
Thanks for the replies
I'm running E38 with 2 connectors.
I'm running stock manifolds, but will recheck for exhaust leaks.
Assume that I need to get a tuner to read and adjust the values for DFCO reference in the link below?
http://www.hptuners.com/help/index.h...uel_cutoff.htm
Well, that's a heck of an investment for such a small problem. When you said the ECM was modified to ignore the rear O2s, I assumed you either had a tuning package already, or were working with a local tune on the car.
I run a GTO with an E40 PCM, HP Tuners, and am not a pro mechanic or tuner...just a DIYer. So keep that in mind, and don't take my word for gospel.
I installed an H-Pipe 70,000 miles ago, but at the same time I had my cam installed. They do help increase scaveging, so that might help if there's nothing else wrong.
I can tell you for sure that when I have my car in "Open Loop" with DFCO disabled, I get a lot more of that popping. I also had more when I burnt a hole through my header gaskets.
Might want to ask some questions on the HP Tuners forums as well...I'm only familiar with the E40.
I run a GTO with an E40 PCM, HP Tuners, and am not a pro mechanic or tuner...just a DIYer. So keep that in mind, and don't take my word for gospel.
I installed an H-Pipe 70,000 miles ago, but at the same time I had my cam installed. They do help increase scaveging, so that might help if there's nothing else wrong.
I can tell you for sure that when I have my car in "Open Loop" with DFCO disabled, I get a lot more of that popping. I also had more when I burnt a hole through my header gaskets.
Might want to ask some questions on the HP Tuners forums as well...I'm only familiar with the E40.
