fast idle

[jms.plumbing]

My "08" 1200xlc idles very fast and for a long time after a short or a long ride. The fast idle may last from 1 to 3 minutes. I had new drag pipes with upgraded air filter and a DFO installed. The motor did not do this right after install and does not do this all the time. I have noticed that it is becoming more and more often. Any answers???

 

[Hoople]

What Hobbit said or maybe sticky IAC stepper motor if no air leak found..

 

[jms.plumbing]

yeah it pops a little if on it hard and let off fast and no codes are shown.

 

[Hoople]

Lite pop No codes. I would then focus on IAC. That is it's job to control idle speed.

 

[67hat34c]

Also there is an error in the ECU that may be corrected with a reflash.

Mine doest the fast idle if i stall it then restart it. Only way to clear it is to shut off the key then re start, sort of resets the ECU.

 

[Hoople]

Mine doest the fast idle if i stall it then restart it. Only way to clear it is to shut off the key then re start, sort of resets the ECU.

Interesting. Are you saying the engine won't settle down on it's own after a re-start from a stall? I can see that the lack of tach input signal to ECM would cause the stepper to climb up for a few seconds but once engine stabilized you would think ECM would regain control of idle. Sounds like firmware bug.

I have to see if my Dyna does that. Never tried it.

 

[keithrobbins]

Bring back the old fashioned carbs I say. Well proven technology and no electronics to go wrong!