View Full Version : How to relearn proper idle after battery disconnected.
zeteckat
09-02-2003, 05:24 PM
Is there anything i have to do besides start my car up without any accessories on? Should i let it idle until the cooling fan cycles for the first time. Is there a set procedure i should follow? I'm looking to get the smoothest idle possible. Thanks
first pull off your negitive battery cable off for 15 min. and then put it back on and start your car...
that will reset your computers.. and idle
NKTasty
09-03-2003, 04:40 PM
As far as I know, the computer doesnt learn a proper idle speed. You can adjust the idle with the set screw in the throttle body, but that really isnt neccessary.
Should be just like Al said- disconnect the battery for a bit, re-connect, then start the car up.
Afterhours
09-04-2003, 03:02 AM
Originally posted by: NKTasty
As far as I know, the computer doesnt learn a proper idle speed. You can adjust the idle with the set screw in the throttle body, but that really isnt neccessary.
Should be just like Al said- disconnect the battery for a bit, re-connect, then start the car up.
The idle or air/fuel mixture cannot be adjusted from the throttle body. The idle air control (IAC) valve adjusts the engine idle. This valve is located on the side of the throttle body. This valve is controlled by a duty cycle signal from the PCM. The PCM duty cycle takes into account various sensor input signals such as engine temp, air intake temp, mechanical loads (such as AC, automatic transmission in gear)....etc, to determine proper idle speed.
After you disconnect the battery (which by the way, resets the PCM) you should drive the car around for a while. It may take a while for the idle to settle in, but it seems like various loads and changing throttle positions help to speed up the process.
zeteckat
09-04-2003, 07:38 PM
When i start the car, should i have the a/c on or off?
When i drive my car around, should i have the a/c on or off?
Thanks
Ness1216
09-04-2003, 11:28 PM
umm shouldnt matter i would think.
zeteckat
09-04-2003, 11:52 PM
I wouldn't think it would have mattered either, but i think it does. I resetted the ecu and when I cranked it i had the a/c on. It didn't seem to like this too much.
I think the computer is counting IAC counts when the car is started for the first time, after the computer is reset, and is trying to learn them. So with the air on during my first start my idle would flucuate quite a bit. I think this is due to the fact that when the a/c cycles and the compressor shuts off the IAC counts are higher at that point due to a higher rpm. The computer then tries to adjust for that. This is all i can come up with. I was just curious to know the procedures you guys use.
Ness1216
09-05-2003, 12:46 AM
hmm that makes me wonder... When I installed intake comp was reset and my idle fluctuates quite a bit. I donno Ill reset if with the ac off to see if it helps.
zeteckat
09-05-2003, 01:41 AM
It couldn't hurt ness. Also, i read in the instruction manual that all accessories must be off on the first start after the computer is reset. Give it a try and remember to let it idle with all accessories off for at least 1 min.
Afterhours
09-05-2003, 02:00 AM
Zeteckat is right. It is better to initially start the car without any additional load, such as the AC. Once the car can hold a fairly steady idle, then you can turn the AC on and drive around a bit. Don't be too concerned if the car dies when coming to a stop a few times. Just re-start it and continue driving. The idle should settle in after 10 minutes or so of driving.