Idle Relearn Procedure?
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Launching!
Joined: Dec 2001
Posts: 206
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From: N. Carolina
Idle Relearn Procedure? One of the Corvette boards gives this tech tip. It states that this procedure needs to be done after any intake system mods. If not done, you could get hesitation or other issues. The procedure involves pulling 10 amp fuses from positions 16 & 23 in the fuse block among other things.
Is this true for the F-body cars as well? If so, what is the proper procedure?
I saw the tech tip here: http://www.c5forum.com/diy/idlerelearn.php
Thanks for all knowledgable replys.
Enjoy your cars.
Is this true for the F-body cars as well? If so, what is the proper procedure?
I saw the tech tip here: http://www.c5forum.com/diy/idlerelearn.php
Thanks for all knowledgable replys.
Enjoy your cars.
Re: Idle Relearn Procedure? Don't know if it is the same on F-bodys, but it is a must on C5s, just putting a new battery in caused all kinds of problems,idle relearn cured them all..
Re: Idle Relearn Procedure? This is a must for my car. After pulling the battery, or disconnecting the PCM.
On first start, the car will barely run, I have to use the throttle to keep it alive. I vary the RPMs between Idle and 2500 a few times, then turn the car off.
On second start, everything is as it should be. It runs fine.
I used to think that I was leaving a plug wire off or something, and after every first start would get out, check the plugs and everything else. Then on next start, it would be fine.
Now, before the car leaves the garage, it is started at least twice.
On first start, the car will barely run, I have to use the throttle to keep it alive. I vary the RPMs between Idle and 2500 a few times, then turn the car off.
On second start, everything is as it should be. It runs fine.
I used to think that I was leaving a plug wire off or something, and after every first start would get out, check the plugs and everything else. Then on next start, it would be fine.
Now, before the car leaves the garage, it is started at least twice.
TECH Resident
Joined: Jan 2002
Posts: 754
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From: USA
Re: Idle Relearn Procedure? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NC Guy:
<strong>One of the Corvette boards gives this tech tip. It states that this procedure needs to be done after any intake system mods. If not done, you could get hesitation or other issues. The procedure involves pulling 10 amp fuses from positions 16 & 23 in the fuse block among other things.
Is this true for the F-body cars as well? If so, what is the proper procedure?
Thanks for all knowledgable replys.
Enjoy your cars.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You do NOT have to pull any fuses just because of a change to the intake.
Also the idle relearn process they give is not correct.
After airflow changes the idle relearn has to be done so PCM can recalibrate the ide circuit when AC is on or off.
Over the years GM has changed the method a bit and relearn prcess is different for a A4 then a MN6.
In simple with MN6,
start engine with AC OFF, let it idle for about 5 minutes.
Then you want to turn AC on full blast (coldest setting) and adle for 5 minutes. This allows PCM to calibrate with the idle trim cells :
Cell 17, cold AC idle
18, at operating temps AC idle
Cell 20, Cold idle, no AC
19, at operating temp, no AC
Now for the next hour of drive time PCM will recal the other fuel trim cells for part throttle and PE modes.
If you yank PCM fuses just for a intake airflow change, the loss of power to PCM causes all the I/M 240 smog tests to be blown out and could cost up to 40 drive cycles to get them back to a PASSed ( complete) state, thus unless you really have to yank power, don't.
<strong>One of the Corvette boards gives this tech tip. It states that this procedure needs to be done after any intake system mods. If not done, you could get hesitation or other issues. The procedure involves pulling 10 amp fuses from positions 16 & 23 in the fuse block among other things.
Is this true for the F-body cars as well? If so, what is the proper procedure?
Thanks for all knowledgable replys.
Enjoy your cars.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You do NOT have to pull any fuses just because of a change to the intake.
Also the idle relearn process they give is not correct.
After airflow changes the idle relearn has to be done so PCM can recalibrate the ide circuit when AC is on or off.
Over the years GM has changed the method a bit and relearn prcess is different for a A4 then a MN6.
In simple with MN6,
start engine with AC OFF, let it idle for about 5 minutes.
Then you want to turn AC on full blast (coldest setting) and adle for 5 minutes. This allows PCM to calibrate with the idle trim cells :
Cell 17, cold AC idle
18, at operating temps AC idle
Cell 20, Cold idle, no AC
19, at operating temp, no AC
Now for the next hour of drive time PCM will recal the other fuel trim cells for part throttle and PE modes.
If you yank PCM fuses just for a intake airflow change, the loss of power to PCM causes all the I/M 240 smog tests to be blown out and could cost up to 40 drive cycles to get them back to a PASSed ( complete) state, thus unless you really have to yank power, don't.
