Ok, got an IAC that may be acting up... Stalling on decel in high heat. Should I use a soft tooth brush along with carb/intake cleaner as a first approach or take the whole thing apart?

 

My bike is doing the same thing. I'll be waiting for answers too......

Trucky911

 

Ive seen several posts about this issue. Several suggest carb or intake cleaner and the part is reachable from the intake throat but I just want to make sure Im not gonna damage the part by giving it a little scrub.

 

IAC motors are rather infamous for losing counts. As an IAC motor wears, they develop "slop" in the thread, to pintle location. The threads on an IAC motor are not metal. As an IAC motor moves, from one polarity to another, the ECM "counts" the movement. As motors get old they get sloppy and can and do wear to the point that they lose counts, during a run cycle. ( The motor resets every time you key off! So on the next key on the motor position is "known.")

But when they wear and start to lose counts, you really need a new IAC motor!

For those that "clean" the housing, there may nave been a little crud in the threads. So try cleaning! ( any change in air rate due to deposits, will be accounted for, so cleaning really isn't a fix for stalls on decel!) The one area where deposits may affect the IAC system is the actual throttle blade to throttle body. The shipping air ( that set by the throttle set screw) has some affect on how an IAC system functions. So try cleaning the actual throttle body BORE also.

But it has been extensive exprience that once an IAC motor starts to lose counts, it is dead and needs to be replaced!

I've calibrated IAC idle control and have even had new motors that lose counts after only a very short amount of time!!
( They all lose or gain a few counts, but when the motor develops too much "slop" btween the threads on the pintle and the motor body, cleaning will not help!!)

One of the many reasons for going to drive by wire, is getting the IAC motors out of the system!! They have always been a leak link in controling IDLE!

 

You should first try the method with the least potential for damaging the sensor. I've cleaned mine with carb cleaner. Some sensors are actually "sensitive" and unless you know for sure it's OK to touch it with a brush or something you might want to stay away from that. I don't have my parts book handy but I will bet it's not a cheap replacement.

 

FBRR, thanks for taking the time for that explanation. Makes sense now. Cleaned it and we will see tomorrow.

 

If you do choose to remove for cleaning make sure bike is powered down and remove connector before removing from throttle body. If you removed while powered up you run the risk of the iac extending itself right out. Its happened to me on a couple of vehicles.

 

Someone mentioned a "sensor". The IAC system is not a sensor, nor does it have a sensor. The only way an IAC motor has a "known" position is when they are reset. ( The reset fully extends the IAC pintle driving it into the seat, then backing it out a set number of "counts." The ECM then "knows" where the pintle position is set.) But once the engine is running an IAC motor is continually driven in and out!

The IAC system not only controls IDLE but has a "throttle follower" function. That is the pintle is moved every time the throttle is opened and closed. How much the or how many counts are added and subtracted depends on the percent of throttle opening. The reason for this "throttle follower" function is two fold. It act at low speed as for throttle opening ( or progression ) feel, and then when the throttle is closed to "cushon" the RPM return to IDLE to prevent under shoots and stalling of the RPM.

What happens when counts are lost, is the ECM attempts to return the IAC pintle the the proper position (airflow) to catch the RPM a little higher than "idle speed" then control the RPM decel back to IDLE. When counts have been lost, the ECM controlled position is far more closed (less than expected airflow) and when you shut down the throttle, the system cannot react fast enough ( from this "lost" position) to keep th engine from stalling.

As I stated above, the "shipping air" ( that which is set by the throttle blade screw ) allows some amount of "calibrated" airflow to pass by the blade and is an additional "known" amount of airflow. As deposits build up on between the throttle blade and throttle body walls, this air rate is reduced. That can have some affect on the calibrated movement of the IAC motor. So cleaning that area of the throttle body might help!

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(Caution, never reset that throttle stop screw! Because you will affected how the IAC motor will function. Either too little or too much "shipping air rate" will cause the IAC idle position ( in counts) to change. The calibration only allows an "idle position" (counts)of limited "authority". So if you move the screw too far either way, the IAC will not function correctly to maintain IDLE speed, and also control "DECEL" RPM as the throttle is closed!

 

I am having the same problem with stalling. Does someone have a pic of the exact place to where to spray the carb cleaner. Just want to do it correctly. Thanks

 

Take off the air cleaner. You are looking into the throttle body opening. At about 11:00 there is a small opening in the body. Spray it there. Turn the ignition on and off and you will see it move. Rinse and repeat.