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Old 10-06-2008
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Idle learning steps?

What are the idle learning steps? i have searched but cannot find the proper procedures.
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Old 10-07-2008
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The IAC duty cycle for each idle speed mode is continually learned and updated throughout the life of the vehicle. The learning is deliberately set to a slow rate for stability. If the PCM loses power or is otherwise reset, the learned values are lost and a set of default IAC flow rates are initially used to allow idling until the PCM can relearn the ideal values.

During the learning process, there could be dips and flares in the idle speed as the engine idle load is significantly changed (A/C compressor on/off, neutral/drive transitions, etc.). Even so, the idle duty cycles will eventually be learned to the same range of values as before the reset.

To avoid the potential for large dips and flares, there is a special quick learn routine available immediately after a PCM memory reset. However, if the truck is driven a short distance, the quick learn strategy is exited and the PCM reverts to the normal slow learn rate from the defaults.



Using the "Quick Learn" Idle Speed Routine:

-Park on level ground; set the parking brake; chock the tires.
-Reset the PCM using a scan tool feature or by disconnecting the PCM from battery power for 5 minutes.
-Turn the headlights and accessories off.
-Set the HVAC blower fan to its lowest ON position (not OFF).
-Start the engine and allow it to idle until it is at operating temperature. (Do not drive it because there is a distance limit that will force the PCM to exit the quick learn routine during a short drive.)
-After the warmup, allow the engine to idle for 1 minute in each of its 4 load modes. The order does not matter.
  • Park w/o A/C
  • Park w/ A/C
  • Drive w/o A/C
  • Drive w/ A/C
-Done


Notes:

-The method outlined above is how I do it. Proceed at your own risk.
-When idling in gear, apply the service brakes. Do not rely on the parking brake.
-Do not touch the throttle during the quick learn.
-Remember that the A/C compressor is allowed to run in 5 of the 8 HVAC mode selector positions. For simplicity, turn the mode selector to NORMAL A/C when A/C compressor load is desired and to OFF when it is not.
-A/C compressor operation disabled when low coil temperature may cause evaporator icing. In winter months in some areas, it may not be possible to run the 'A/C on' part of the quick learn procedure. For the best chance at a complete learn, try to run it when the ambient temperature is 40F or higher.
-Trucks with manual transmissions only have 2 load modes to learn:
  • Neutral w/o A/C
  • Neutral w/ A/C
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Old 10-08-2008
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thanks
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Old 10-09-2008
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Excellent Bob.

The only thing I'll add is something I've observed on my 06. When you clear the computer with a reflash, or because of disconnecting the battery. No matter what the engine temp is, you'll feel the motor stumble a little bit over the next few minutes.

This is normal because the computer is sweeping the a/f from very rich to very lean. It takes approximately 1 minute to do this. Don't be alarmed if you feel it spit and sputter after the flash/clear.

Rich
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Old 10-16-2008
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idk but these steps didnt work for me. I tried several times. ????????
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Old 10-16-2008
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How do you know that it didn't learn? I have watched the IAC duty cycle with a factory tool many times using these steps and it has always worked.
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Old 10-16-2008
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I mean it is still idling around 500-600 rpms. It may have worked. I just didnt notice any change. I will try again tomorrow.
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Old 10-16-2008
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I might be doing something wrong. IDK
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Old 10-16-2008
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The PCM does not learn the idle speed - that is programmed into the calibration. Instead, it is learning the IAC duty cycle that will produce the desired idle speed in the each of the 4 different load modes. This learning allows the PCM to anticipate the required duty cycle when the vehicle switches between load modes (like neutral to drive or when the A/C compressor cycles on and off). Anticipating the load change (instead of reacting to the load change) helps to prevent annoying dips or flares in the idle speed when the load on the engine changes.

If the idle speed is not correct, IAC learning cannot fix it.
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Old 10-16-2008
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Is idle speed a timing issue or computer or what? How do you idle it up or down?
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Old 10-16-2008
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The idle speed is controlled 100% by the PCM calibration. The desired idle speed for any combinationation of PCM inputs can only be changed in the calibration and that can only be done by reflashing it.

I don't know exactly what your engine idle is supposed to be but warm engine idle is typically calibrated to somewhere around 650~750 RPM. If it is idling lower than it should, it could be a mechanical problem like a stuck IAC or a mixture problem such as a vacuum leak, unmetered air leak or dirty MAF.
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Old 10-16-2008
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Thanks I might get it reflashed or clean my maf
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Old 10-17-2008
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If the calibration is still factory stock, then the PCM is already flashed to the correct value. Reflashing it will not help. I would look first for a dirty IAC, then vacuum or air leaks, then the MAF.
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Old 10-17-2008
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My 06 stock ford tune commands 754 rpms for both Neutral and Drive.

Rich
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Old 03-06-2009
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replying to find easyer
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