Tuning question
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Intermediate
Joined: Feb 2019
Posts: 26
Likes: 4
Tuning question
I have an 03 C5 with the LS-1 and a 6 speed. Mileage is 65,000. It has an annoying exhaust pop on trailing throttle when it is cold and sometimes when it is hot. Sounds like it is coming off the right bank. Runs great and pulls like a freight train. It has a Corsa exhaust and a smooth intake boot between the airfilter and the intake. No other changes to it , Wires/boots replaced about 7K ago. Is this a tuning/injector thing that is correctable or should I just put up with it?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,564
Likes: 4,034
From: Cape Coral, Florida
When I got rid of my stock exhaust system and installed Borla Stingers I did notice that exhaust 'pop" on decel !!....installed and X pipe it basically went away !!
Drifting
Joined: Oct 2002
Posts: 1,773
Likes: 66
From: SoCal
Yes. Usually after you install an aftermarket catback you can get the pop on decel. The X pipe is before the mufflers in the midpipe. Stock midpipe has an H pipe with a tiny hole in it. Not a straight 2 1/2 inch pipe. The X pipe pretty much gets rid of the popping, or fully does.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Typically an exhaust popping on an un modded bolt on only engine is due to an exhaust leak Especially since you have an aftermarket exhaust
Popping is normally caused by fresh air being sucked into the exhaust stream during decel and that cold air causes the popping----
Sometimes even a small exhaust leak will cause this The best way to see if you have an in audible leak is to data log your LTFT or fuel trims---The side with the leak will show a mismatch in your LTFT's between the left and right banks
Normally the side with the exhaist leak will show
1. a hiigher front 02 voltage average on the leak side
2. the fuel trim corrections on the leak side will have a more POSITIVE fuel trim correction than the non leak side--------when you have an exhaust leak the side with the leak will not heat up the front 02's properly so the ECM thinks that itis lean and adds fuel-----This extra fuel upon decel will ignite and cause the popping as that fuel ignites from the cold air from the exAnyinehaur leak
Anyone with a simple good scan tool should be able to read both sides of your front 02 voltage averages and the LTFT or fuel trim corrections
Popping is normally caused by fresh air being sucked into the exhaust stream during decel and that cold air causes the popping----
Sometimes even a small exhaust leak will cause this The best way to see if you have an in audible leak is to data log your LTFT or fuel trims---The side with the leak will show a mismatch in your LTFT's between the left and right banks
Normally the side with the exhaist leak will show
1. a hiigher front 02 voltage average on the leak side
2. the fuel trim corrections on the leak side will have a more POSITIVE fuel trim correction than the non leak side--------when you have an exhaust leak the side with the leak will not heat up the front 02's properly so the ECM thinks that itis lean and adds fuel-----This extra fuel upon decel will ignite and cause the popping as that fuel ignites from the cold air from the exAnyinehaur leak
Anyone with a simple good scan tool should be able to read both sides of your front 02 voltage averages and the LTFT or fuel trim corrections
Advanced
Joined: Oct 2017
Posts: 88
Likes: 21
Yes. Usually after you install an aftermarket catback you can get the pop on decel. The X pipe is before the mufflers in the midpipe. Stock midpipe has an H pipe with a tiny hole in it. Not a straight 2 1/2 inch pipe. The X pipe pretty much gets rid of the popping, or fully does.
Instead of an X-pipe a better solution is retune the fuel mixture to the new exhaust to prevent the popping completely.
Last edited by VETTLIFE; Mar 8, 2019 at 08:54 AM.
