fast idle

Discussion in 'Sportster Models' started by jms.plumbing, Mar 29, 2010.

  1. jms.plumbing

    jms.plumbing New Member

    2
    0
    0
    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???
     
  2. Hoople

    Hoople Account Removed

    7,198
    0
    34
    What Hobbit said or maybe sticky IAC stepper motor if no air leak found..
     
  3. jms.plumbing

    jms.plumbing New Member

    2
    0
    0
    yeah it pops a little if on it hard and let off fast and no codes are shown.
     
  4. Hoople

    Hoople Account Removed

    7,198
    0
    34
    Lite pop No codes. I would then focus on IAC. That is it's job to control idle speed.
     
  5. 67hat34c

    67hat34c Active Member

    297
    26
    0
    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.
     
  6. Hoople

    Hoople Account Removed

    7,198
    0
    34
    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.
     
  7. keithrobbins

    keithrobbins New Member

    1
    0
    0
    Bring back the old fashioned carbs I say. Well proven technology and no electronics to go wrong!