idle relearn
04-24-2007, 08:16 AM
#1
Instructor
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idle relearn
What is "idle relearn"? I've noticed my '00 A4 has a little bit of a rough idle lately. Noticed it the first time as I was backing into a parking space Sunday. Tach would drop down to 500 or so, and then it would smooth out. Seem to notice it when the A/C is running, and the fan is running high. Checked the DIC, and it showed 13.5-13.7 volts at that time. Everything seemed OK at highway speeds right after that. Did it again yesterday afternoon as I was pulling into the driveway. Any thoughts?
04-24-2007, 09:33 AM
#2
Race Director
Idle relearn is a procedure that allows the PCM to recalibrate air/fuel ratios. This procedure may be requried after changing an air intake, MAF, porting a throttle body etc.
It should norrmally not be required if no changes have been made One exception.. . ( there may be others) If you have recently changed from an alcohol free to an alcohol containing gasoline, you will have leaned out your air/fule mixture.
Idle Learn Procedure
Automatic Transmission
Perform the following procedure in order to return the learned idle to the correct position:
1] Turn OFF the ignition.
2] Restore the PCM battery feed (if disconnected).
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Start the engine.
6] Ensure that the engine coolant temperature is more than 80°C (176°F).
7] Shift the transmission into Drive.
8] Allow the engine to idle for 5 minutes.
9] Shift the transmission into Park.
10] Allow the engine to idle for 5 minutes.
11] Turn OFF the engine for 30 seconds.
Manual Transmission
Perform the following procedure in order to return the learned idle to the correct position:
1] Turn OFF the ignition.
2] Restore the PCM battery feed.
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Place the transmission in Neutral.
6] Start the engine.
7] Ensure that the engine coolant temperature is more than 80°C (176°F).
8] Allow the engine to idle for 5 minutes.
9] Turn OFF the engine for 30 seconds.
The A/C compressor kicking in and out at idle speeds puts a high load on the engine at those rpms and will affect idle speeds on most Vettes... Some with modified cams have a very rough idle and may stall with the A/C on at idle...
It should norrmally not be required if no changes have been made One exception.. . ( there may be others) If you have recently changed from an alcohol free to an alcohol containing gasoline, you will have leaned out your air/fule mixture.
Idle Learn Procedure
Automatic Transmission
Perform the following procedure in order to return the learned idle to the correct position:
1] Turn OFF the ignition.
2] Restore the PCM battery feed (if disconnected).
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Start the engine.
6] Ensure that the engine coolant temperature is more than 80°C (176°F).
7] Shift the transmission into Drive.
8] Allow the engine to idle for 5 minutes.
9] Shift the transmission into Park.
10] Allow the engine to idle for 5 minutes.
11] Turn OFF the engine for 30 seconds.
Manual Transmission
Perform the following procedure in order to return the learned idle to the correct position:
1] Turn OFF the ignition.
2] Restore the PCM battery feed.
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Place the transmission in Neutral.
6] Start the engine.
7] Ensure that the engine coolant temperature is more than 80°C (176°F).
8] Allow the engine to idle for 5 minutes.
9] Turn OFF the engine for 30 seconds.
The A/C compressor kicking in and out at idle speeds puts a high load on the engine at those rpms and will affect idle speeds on most Vettes... Some with modified cams have a very rough idle and may stall with the A/C on at idle...
Last edited by rws.1; 04-24-2007 at 09:35 AM.
12-14-2007, 11:52 PM
#4
Melting Slicks
Member Since: May 2007
Location: Houston TX
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Idle Learn Procedure
Automatic Transmission
Perform the following procedure in order to return the learned idle to the correct position:
1] Turn OFF the ignition.
2] Restore the PCM battery feed (if disconnected).
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Start the engine.
6] Ensure that the engine coolant temperature is more than 80°C (176°F).
7] Shift the transmission into Drive.
8] Allow the engine to idle for 5 minutes.
9] Shift the transmission into Park.
10] Allow the engine to idle for 5 minutes.
11] Turn OFF the engine for 30 seconds.
Automatic Transmission
Perform the following procedure in order to return the learned idle to the correct position:
1] Turn OFF the ignition.
2] Restore the PCM battery feed (if disconnected).
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Start the engine.
6] Ensure that the engine coolant temperature is more than 80°C (176°F).
7] Shift the transmission into Drive.
8] Allow the engine to idle for 5 minutes.
9] Shift the transmission into Park.
10] Allow the engine to idle for 5 minutes.
11] Turn OFF the engine for 30 seconds.
12-15-2007, 12:22 AM
#5
Tech Contributor
Member Since: Oct 1999
Location: Charlotte, NC (formerly Endicott, NY)
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Driving the car for 20 miles will also get the PCM to learn new operating conditions. All the idle relearn procedure does is wipe out the old memory so you start from a scratch baseline. Have never done it even after making mods. Never noticed a problem.
Bill
Bill
12-15-2007, 12:48 AM
#6
Melting Slicks
Member Since: May 2007
Location: Houston TX
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did you have a larger TB installed?Mine was running great till I installed it.
