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Iac

I already bought the new one. I really do not want to mess around, I just want to fix it, and like Hoople said, I was surprised at the price of these parts, they are not that expensive, so I just figure not to 2nd guess it just replace it. Now I guess I really need to get to new the fuel injected bikes, man I miss my carb., oh well, if the dealer does not want to fix it, then I will, then I will let them know what they overlooked or missed. Hey, one more question, could the IAC cause a low idle even if it was turned up through the SERT?

Hey Hoople and Glider, if I haven't said thank-you for all the helpful info, then let me do it now, Thank-you very much. I also need to thank Smitty to, you guys are helping me narrow this problem down. :small3d018::small3d018:

Hoople, just reread all the posts, the guy at the other dealer said this is the first thing he would change, that is why I am starting here, so we will see.
 
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Drumrguy said:
I already bought the new one. I really do not want to mess around, I just want to fix it, and like Hoople said, I was surprised at the price of these parts, they are not that expensive, so I just figure not to 2nd guess it just replace it. Now I guess I really need to get to new the fuel injected bikes, man I miss my carb., oh well, if the dealer does not want to fix it, then I will, then I will let them know what they overlooked or missed. Hey, one more question, could the IAC cause a low idle even if it was turned up through the SERT?
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You have to remember 1 important fact. The IAC does not have any feedback control in itself. Meaning, the only feedback the ECM gets is from the crank sensor in the form of an RPM count.
Example: Lets say the actual idle is 850 RPM, but the Idle MAP says it should be 1000 RPM. In this case the ECM will tell the IAC to sep up the idle, but the ECM does NOT know exactly what "step" the idc is at any given time. There is no feedback in the IAC that says to the ECM "I am at step XYZ". It send the sep count "out" and we hope it reacts.

So to answer your question....Yes, if it was stuck.

Hoop!
 
$35 is cheap. I had to pay 75 Euro in Holland for an IAC I really didn't need. cleaning with cargb cleaner at the end would have been enough.
 
Mine was starting to stall off and on earlier in the summer. Can of carb cleaner..sprayed it down good (little hole on the upper side of the intake) and hasen't stalled since...2.99 VS 35.00....it's worth a shot.
 
I probably should mention that the $35.00 price was from Lakeshore HD after the discount. But even MSRP price is not too too bad for an electrical part.
 
I think the part listed for 52.00 minus my 15% discount, and it was in stock, so that was not too bad. Hopefully it works! I will change it tomorrow and post an update, but in the meantime if anyone can think of anything else, please let the ideas keep coming, I am on my own with this problem.
 
Drumrguy said:
but in the meantime if anyone can think of anything else, please let the ideas keep coming, .
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Ignition timing that was not advanced enough at idle would certainly be on the hit list. Do you know what your Base timing is at idle on each cylinder.
 
Hoople said:
In this case the ECM will tell the IAC to sep up the idle, but the ECM does NOT know exactly what "step" the idc is at any given time. There is no feedback in the IAC that says to the ECM "I am at step XYZ". It send the sep count "out" and we hope it reacts.
Click to expand...
I think "well, yes and no". I'm not exactly sure at the moment, but I believe the ECM keeps track of where it needed to be and on boot-up, cranks it all the way closed, then counts out the number it wants. And I wouldn't be surprised if there isn't some type of feedback within the driving circuit as to whether or not it's actually moving/moved.

I was thinking there was a DTC for the idle air...

At any rate, there are multiple steps per revolution (not saying that to contradict glider - it just depends on what H-D's definition of "is" is, so to speak). That's the way a stepper motor works. They're pretty high-torque, too. Probably the more steps per revolution, the higher the torque. And the "rotor" can be positioned pretty discretely, more so with more steps per revolution.

Does anyone know what kind of thread pitch the rotor/plunger uses? It could be a pretty lazy thread (low pitch count).

Wikipedia probably has an article on "stepper motors".

Heck, maybe the bike stalls because the dirty plunger is now hot and everything's expanded a little so the grit is impeding movement and overcoming the motor's torque. Maybe the ECM is thinking "where the heck is that thing, anyway?" so it performs a quick (what would usually be quick-enough to go unnoticed) little reset by closing and counting out to the current preset. Only now it ain't working fast enough 'cause it's dirty and hot. Just some conjecture on my part. Thanks for listenin'
 
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