POP thru intake - misses too

Discussion in 'Engine, Fuel and Exhaust' started by stevewaxy, Oct 27, 2008.

  1. stevewaxy

    stevewaxy New Member

    1999 Twin Cam - 125,000 on it but ,rebuilt engine at about 115,000. It has EFI with Power Comander. It has run good all its life till now. The signs and symptoms are as follows: pops thru air cleaner - sometimes at idle (continues running sounds like a cough) other times when I grab the throttle...
    it also intermittenly has a high idle...(like when I stop at a red light...it will idle at 12 or 13 hundred, Can not kick it down...but next light usually ok)
    Another thing, while idling, the idle will just dive down(like I shut the switch off) but then recover itself and contine to idle...when it does this it will contine to happen every 20 or 30 second intervals.
    with all that said.....Once I am on the highway and moving along... the bike purrs like a big kitty....
    also 20 or 30 minutes of hard local riding such as parading...the bike runs great! but I gotta keep it HOT for it to run good. If I shut it off fo 10 minuets...I am back where I started.

    I did find a code once a couple a weeks ago and replaced the CPS (cam position sensor)
    it ran ok for a week ...
    now its not

    signed fustrated
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    No codes but that one? What was included in the rebuild?

  3. glider

    glider Veteran Member

    Your info about running OK when hot and acting up when cold makes me think the cylinder head temp sensor may be going bad on the rear of the front head. May be time to get a diagnostic done on it.

    You have a Morelli system on that bike.
    Start out by cleaning out the air bleed holes in the throttle body with some spray carb cleaner with the straw nozzle on it and see if it makes a difference. They are small pin holes (2) in the inner throttle body of the intake system at the 10 O' clock position for the front runner and the 2 O' clock position for the rear runner.Give them a good cleaning and see if it helps.
    Check this out too...

    Magnetti Marelli Idle - Harley Davidson Community
    Last edited: Oct 27, 2008
  4. stevewaxy

    stevewaxy New Member

    Rebuild was new heads, jugs and I guess bearing in the bottom...
    did not touch the fuel system