High idle. IAC problem?
Thread Starter
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Cruiser
Joined: Jan 2020
Posts: 145
Likes: 18
From: Mass
High idle. IAC problem?
Hi. 2008 FXD is idling at start up around 2k rpm, then slows down to about 1600-1700. I had the throttle body bored to 50mm and the butterfly is definitely a tiny bit loose.
I swapped the IAC with a new fueling one. Same problem. When I put my finger over the hole in the throttle body idle doesn't change. tried it on my friends bikes and it stalls them immediately. Could this be another issue somewhere further down the line? Thanks in advance
I swapped the IAC with a new fueling one. Same problem. When I put my finger over the hole in the throttle body idle doesn't change. tried it on my friends bikes and it stalls them immediately. Could this be another issue somewhere further down the line? Thanks in advance
Thread Starter
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Cruiser
Joined: Jan 2020
Posts: 145
Likes: 18
From: Mass
Yes. He makes the throttle plates to fit. There is a tiny bit of play though. Ill get a picture when i take it the AC off later. I think the main problem is with the IAC as I can't control the idle at all when I cover the hole with my finger
Road Warrior
Joined: Aug 2008
Posts: 1,306
Likes: 865
From: Sheboygan, WI
the hole you are covering is the path for the iac air. Since covering it on yours has no effect on engine speed, it proves that your problem is NOT the iac. You have too much air getting to the engine past the throttle blade or via intake leaks.
Thread Starter
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Cruiser
Joined: Jan 2020
Posts: 145
Likes: 18
From: Mass
interesting 🤔. I've tried spraying brake cleaner cleaner everywhere on the induction module and can't get it to Rev up
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Road Warrior
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Road Warrior
Joined: Mar 2013
Posts: 1,923
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From: Alorton, Illinois
Do have any tuning device that will allow you to watch IAC position? The air leak is probably your throttle blade. I would back out throttle stop until the blade is closed enough to have to have a couple of IAC control idle speed. If throttle blade is all the way closed and still has too much air. You can loosen screws and try to reset where the blade is in the bore. I'd recommend being careful and red lock tight the screws.
Seasoned HDF Member
Joined: Jul 2008
Posts: 9,282
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From: southeast PA
Bring it back to the shop. Since you had the throttle plate custom made to fit, I suspect it doesn't fit and you can fiddle with it all you want to no avail. Until your tech gets it right you'll be looking for a band aid.
