Tune Problem?
Thread Starter
Drifting
Joined: Apr 2001
Posts: 1,779
Likes: 6
From: LOS ANGELES CA.
Tune Problem?
Happy holidays guys and gals.I have a problem with my 2009 Vette.It is a Coupe.A few months ago I took my car in to have the catalytic convertors replaced under the recall.Performance greatly improved and I was glad I had the recall done.I have noticed that if I drive my car around town without driving on the Freeway,my car loses pick up and temds to buck alittle on acceleration.If I take my car on the freeway and drive about 10+miles,the performance improves. I think its in the tuning which the Agency modified when doing the recall.Any suggestions?
:fla g:
:fla g:
Last edited by ROD BROWN; Dec 25, 2015 at 11:11 AM.
Safety Car
Joined: Nov 2007
Posts: 4,446
Likes: 877
From: Bay Area CA
Happy holidays guys and gals.I have a problem with my 2009 Vette.It is a Coupe.A few months ago I took my car in to have the catalytic convertors replaced under the recall.Performance greatly improved and I was glad I had the recall done.I have noticed that if I drive my car around town without driving on the Freeway,my car loses pick up and temds to buck alittle on acceleration.If I take my car on the freeway and drive about 10+miles,the performance improves. I think its in the tuning which the Agency modified when doing the recall.Any suggestions?:fla g:
:fla g:Some of us have notice the exhaust has become a little louder over a few hundred miles and with some WOT blasts. In other words, more like normal NPP exhaust sound.
As far as the buck around town, put on a few hundred miles along with some WOT blasts and see if that helps, otherwise I would bring it back in or get an aftermarket tune.
Last edited by Mike's LS3; Dec 25, 2015 at 11:46 AM.
Race Director
Joined: Dec 2013
Posts: 12,513
Likes: 3,638
Mike, just our of curiosity, what software are you using, and is it allowing you to see all the ECM programming changes?
Hence the changes may be in the reaction tables such as sensitive and clocking speeds of the over all programming the differences, with you only being able to see the changes in the closed loop 02 rich/lean threshold limits only instead.
Hence it would not surprise me to the least if GM desensitized the throttle mapping even more to try to gain the needed lower emissions that way too, such as slowing down the speed rate of the actual TB vain opening rates .
Hence the changes may be in the reaction tables such as sensitive and clocking speeds of the over all programming the differences, with you only being able to see the changes in the closed loop 02 rich/lean threshold limits only instead.
Hence it would not surprise me to the least if GM desensitized the throttle mapping even more to try to gain the needed lower emissions that way too, such as slowing down the speed rate of the actual TB vain opening rates .
Last edited by Dano523; Dec 25, 2015 at 06:57 PM.
Safety Car
Joined: Nov 2007
Posts: 4,446
Likes: 877
From: Bay Area CA
Mike, just our of curiosity, what software are you using, and is it allowing you to see all the ECM programming changes?
Hence the changes may be in the reaction tables such as sensitive and clocking speeds of the over all programming the differences, with you only being able to see the changes in the closed loop 02 rich/lean threshold limits only instead.
Hence it would not surprise me to the least if GM desensitized the throttle mapping even more to try to gain the needed lower emissions that way too, such as slowing down the speed rate of the actual TB vain opening rates .
Hence the changes may be in the reaction tables such as sensitive and clocking speeds of the over all programming the differences, with you only being able to see the changes in the closed loop 02 rich/lean threshold limits only instead.
Hence it would not surprise me to the least if GM desensitized the throttle mapping even more to try to gain the needed lower emissions that way too, such as slowing down the speed rate of the actual TB vain opening rates .
No changes in Airflow - Electronic throttle.
PM sent.
Last edited by Mike's LS3; Dec 25, 2015 at 10:30 PM.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Whenever your ECM is reflashed-----It sets all your P/T fuel trims to "0" and they must be learned out----The more mods you have on your car the longer it takes--Typically an all STOCK car will even take 50-75 miles of normal driving for the trims to learn out---If you have a cat back or CAI it may take longer-----
While your ECM is learning it typically is ADDING fuel at P/T to compensate for your mods---No big deal at P/T however as a lean safety the ECM will also add that same % to your WOT fuel as well until it learns out----This added % can be as much as 20% which will make your WOT fuel pig rich---lazy and bucky---
And finally GM often will update the STOCK tuning file any time the car is brought into the dealer for any repairs whether you ask for it or NOT----They often get updated new files for even an older car-mostly attributed to smog OR TQ management as the previous poster said-- New smog laws now days sucks !!
While your ECM is learning it typically is ADDING fuel at P/T to compensate for your mods---No big deal at P/T however as a lean safety the ECM will also add that same % to your WOT fuel as well until it learns out----This added % can be as much as 20% which will make your WOT fuel pig rich---lazy and bucky---
And finally GM often will update the STOCK tuning file any time the car is brought into the dealer for any repairs whether you ask for it or NOT----They often get updated new files for even an older car-mostly attributed to smog OR TQ management as the previous poster said-- New smog laws now days sucks !!
Thread Starter
Drifting
Joined: Apr 2001
Posts: 1,779
Likes: 6
From: LOS ANGELES CA.
Thank you
Whenever your ECM is reflashed-----It sets all your P/T fuel trims to "0" and they must be learned out----The more mods you have on your car the longer it takes--Typically an all STOCK car will even take 50-75 miles of normal driving for the trims to learn out---If you have a cat back or CAI it may take longer-----
While your ECM is learning it typically is ADDING fuel at P/T to compensate for your mods---No big deal at P/T however as a lean safety the ECM will also add that same % to your WOT fuel as well until it learns out----This added % can be as much as 20% which will make your WOT fuel pig rich---lazy and bucky---
And finally GM often will update the STOCK tuning file any time the car is brought into the dealer for any repairs whether you ask for it or NOT----They often get updated new files for even an older car-mostly attributed to smog OR TQ management as the previous poster said-- New smog laws now days sucks !!
While your ECM is learning it typically is ADDING fuel at P/T to compensate for your mods---No big deal at P/T however as a lean safety the ECM will also add that same % to your WOT fuel as well until it learns out----This added % can be as much as 20% which will make your WOT fuel pig rich---lazy and bucky---
And finally GM often will update the STOCK tuning file any time the car is brought into the dealer for any repairs whether you ask for it or NOT----They often get updated new files for even an older car-mostly attributed to smog OR TQ management as the previous poster said-- New smog laws now days sucks !!
Thread Starter
Drifting
Joined: Apr 2001
Posts: 1,779
Likes: 6
From: LOS ANGELES CA.
Still running rough
Its been quite a while since the dealership replaced the mufflers and the catalytic converters.My car still isn't running as it should.I guess the car will have to go back to the dealer.The car runs great after driving on the freeway,but around town its lacking in power.Rod
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Absolutely would take it back for warranty fix----A tuner can data log what's going onand tell you the cause--- but you would have to pay for that----According to the previous post seems like GM has either changed the front 02 locations or the front o2 switching points---This all has to do with P/T driving and not WOT--so it seems this is where your issue lies-----I suspect that after the cat change---your fuel trims never completely learned out--causing you fueling issues---Normally they self correct after 50 miles of normal driving but it seems yours didn't---Any change or correction beyond approx. 20-25% will NEVER learn out and cause codes and or P/T issues--
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Race Director
Joined: May 2004
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From: Raleigh, NC
St. Jude Donor '15
I've seen a few tunes before/after this warranty work and they were nearly identical. Maybe this one is different.. but the switch points were not changed in all the rest I've seen.