Could be a wiring issue as well like chafed wiring or corrosion in a connector throwing off the sensor readings.Hard to say what you're up against without getting a scan tool of some sort connected to it.Good luck.

 

Injectors are not leaking, thanks Baird for the idea

 

Just to be clear, with IAC back in the game, on startup idles normal, after throttle opening and back to idle rpms are high.
Other than replacing the IAC, did you clean the port the pintle resides in?
Know anyone with a Powervision? I think you can hook it up to your bike and it will let you view inputs/outputs. you need to know if throttle position gets back to 0% You can also monitor IAC steps

 

Thanks yeah that's correct, yes cleaned out the port and the seat where the IAC sits. If you take the air cleaner off you can see it sitting up off the seat at high idle, probably about 3.5-4mm, its open really wide. Reset, clear error code and it goes back to about 1mm, idle is about 1,100 warm at the lowest, so that's the point where i've disconnected the IAC at, otherwise its dangerous to ride. Don't know anyone with Powervision, its booked in at the local Harley dealer in a week or so, they didn't have a booking for 3 weeks, I think i'll now park it till they look at it. I've pulled off every connector I can find and cleaned them all with contact cleaner, checked the ECM earth, throttle position sensor resistance changes with throttle. It's a weird one.

 

Yes it's a weird and difficult one.
Please when you get it resolved let us know the diagnosis. So many come here with an issue , get advice and never share what the fix was.

 

1. Sticky IAC
2. Loose throttle stop screw.
3. Intake leak.

 

Hi guys, so I got the bike into the Harley shop, all tests conducted, it turns out that the ECM is faulty and needs replacing, also needs a tuner as it's stage 1 and the map wasn't changed. Not the answer I wanted, but an answer ...

 

I wasn't far off in my assement after all.Glad you got it sorted.

 

I just came across this today and was gonna ask if you had a tuner, since you didn't mention one. For the future if you decide to do electrical testing it's a great idea to purchase the electrical diagnostic service manual as well. That will allow you to do tests for the fault codes and also run tests to check wires, sensors, etc. for various equipment.

Ride safe!

 

At this point, I'd wonder if a Tmax would be cost effective.. Anyway let us know how it goes.

I have trouble with the ECM causing high idle if it can control the IAC at all.. The ecm determines idles speed by an internal clock and if it can set the idle at all ist should be able to adjust it.. At turn on it set the idle at a default position and it seem to be doing so as you say you can disconnect it and hot idle is works..

Good luck.. Hope you get it fixed.