Adaptive Idle issues
Thread Starter
Instructor
Joined: May 2009
Posts: 108
Likes: 0
From: Mechanicsville Maryland
Adaptive Idle issues
Having problems with my idle in my 1998 vette. The idle is really rough car has ms3 cam 3800 stall long tubes etc. The adaptive idle wont come on so it just cuts off when come to a stop ..sticks at 1100rpm for about a min then jumps to 300 Tryn to stall out..then 1000.. if coming to a stop it cuts off.. need a fix..
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Having problems with my idle in my 1998 vette. The idle is really rough car has ms3 cam 3800 stall long tubes etc. The adaptive idle wont come on so it just cuts off when come to a stop ..sticks at 1100rpm for about a min then jumps to 300 Tryn to stall out..then 1000.. if coming to a stop it cuts off.. need a fix..
http://forums.corvetteforum.com/sout...d-dec-2nd.html
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
With so many mods tuning is absolutely required--and sometimes it takes more than 1 trip to the tuner---as you should let the ECM learn out some in between changes
Typically when it dies when coming to a stop--
Most common fix is to adjust the "throttle follower " table
also :
with cams
1.you should add 2-4 * of timing to the "base timing " in gear and in P/N
2. ADD a % (3-10% to the "desired airflow table")
3. lean out the "commanded fuel open loop normal" in the start up fuel range ( for cold starts)
for headers:
1. lower you 02 switching points (make sure your 02 voltages are oscillaing beween .100 and .950 and not flatlined at .450
2 make sure all your LTFT's are at "0" or slightly negative ( adjust with your MAF table)
In extreme cases of dying/surging at lift--you can "turn off" your LTFT's
Typically when it dies when coming to a stop--
Most common fix is to adjust the "throttle follower " table
also :
with cams
1.you should add 2-4 * of timing to the "base timing " in gear and in P/N
2. ADD a % (3-10% to the "desired airflow table")
3. lean out the "commanded fuel open loop normal" in the start up fuel range ( for cold starts)
for headers:
1. lower you 02 switching points (make sure your 02 voltages are oscillaing beween .100 and .950 and not flatlined at .450
2 make sure all your LTFT's are at "0" or slightly negative ( adjust with your MAF table)
In extreme cases of dying/surging at lift--you can "turn off" your LTFT's
Safety Car
Joined: Jul 2005
Posts: 3,572
Likes: 9
From: Jackson Tn
St. Jude Donor '06-'07-'08-'09
With so many mods tuning is absolutely required--and sometimes it takes more than 1 trip to the tuner---as you should let the ECM learn out some in between changes
Typically when it dies when coming to a stop--
Most common fix is to adjust the "throttle follower " table
also :
with cams
1.you should add 2-4 * of timing to the "base timing " in gear and in P/N
2. ADD a % (3-10% to the "desired airflow table")
3. lean out the "commanded fuel open loop normal" in the start up fuel range ( for cold starts)
for headers:
1. lower you 02 switching points (make sure your 02 voltages are oscillaing beween .100 and .950 and not flatlined at .450
2 make sure all your LTFT's are at "0" or slightly negative ( adjust with your MAF table)
In extreme cases of dying/surging at lift--you can "turn off" your LTFT's
Typically when it dies when coming to a stop--
Most common fix is to adjust the "throttle follower " table
also :
with cams
1.you should add 2-4 * of timing to the "base timing " in gear and in P/N
2. ADD a % (3-10% to the "desired airflow table")
3. lean out the "commanded fuel open loop normal" in the start up fuel range ( for cold starts)
for headers:
1. lower you 02 switching points (make sure your 02 voltages are oscillaing beween .100 and .950 and not flatlined at .450
2 make sure all your LTFT's are at "0" or slightly negative ( adjust with your MAF table)
In extreme cases of dying/surging at lift--you can "turn off" your LTFT's
Thread Starter
Instructor
Joined: May 2009
Posts: 108
Likes: 0
From: Mechanicsville Maryland
Correct... it dosent come on.. Where to i check to make sure nothing is loose.. is there a sensor? Yesterday I started it and it ran fine and drove fine.. Also this morning I drove it to work ran fine then got on a bumpy road and after that it wanted to cut off at a light when just at idle..Loose connection?
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Correct... it dosent come on.. Where to i check to make sure nothing is loose.. is there a sensor? Yesterday I started it and it ran fine and drove fine.. Also this morning I drove it to work ran fine then got on a bumpy road and after that it wanted to cut off at a light when just at idle..Loose connection?
Second, you can't really tell from just driving it if the adaptive idle parameters are working or not. You actually have to scan it using the proper PIDs.
If you're having surging and return to idle problems, it's most likely a tuning issue. A very common one.
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Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
The only real "adaptive learning" as fr as i can see is only for the A4 trans shift times and for the knock sensors
If you are speaking about "learning" as far as the LTFT's are concerned that's something entirely different---Typically there is NO
need to adjust the parameters for enabling your LTFT system---It will enable usually enable at 104* and disable at 284* Sometimes on big
cams however it is disabled on purpose
If you are speaking about "idle airflow learning" again usually no need to make adjustments to the "desired airflow table" once tuned-- this learning is enabled at 176* and disabled at 234*
If this is a new issue and it worked fine before---It is most likely it's your LTFT learning---Typically it points to a slow or faulted 02 sensor which keeps the ECM is "Open Loop" all the time where there is NO learning going on---
If you determine it's not your LTFT's and suspect the idle airflow learning--I never make any changes to the "learning part" of your idle airflow but rather to the ACTUAL deired airflow table----I see no reason to change HOW/WHEN it learns--but rather WHAT it learns to---
(IMHO)--- an adjustmet may be needed--But it would be a problem that has been there from day one of your tune and not something new--
If you are speaking about "learning" as far as the LTFT's are concerned that's something entirely different---Typically there is NO
need to adjust the parameters for enabling your LTFT system---It will enable usually enable at 104* and disable at 284* Sometimes on big
cams however it is disabled on purpose
If you are speaking about "idle airflow learning" again usually no need to make adjustments to the "desired airflow table" once tuned-- this learning is enabled at 176* and disabled at 234*
If this is a new issue and it worked fine before---It is most likely it's your LTFT learning---Typically it points to a slow or faulted 02 sensor which keeps the ECM is "Open Loop" all the time where there is NO learning going on---
If you determine it's not your LTFT's and suspect the idle airflow learning--I never make any changes to the "learning part" of your idle airflow but rather to the ACTUAL deired airflow table----I see no reason to change HOW/WHEN it learns--but rather WHAT it learns to---
(IMHO)--- an adjustmet may be needed--But it would be a problem that has been there from day one of your tune and not something new--
