Resetting the IAC motor.

[ChrisCairns]

Is there a way to reset it with a FAST equipped car?

Thanks.

 

[Buzzard]

IAC Controls

Your IAC is set up from the values in the Idle functions menu. Go to View, Idle functions. From there you can see the Iac Position VS coolant temp, throttle follower and idle parameters. What specific issue are you having, if the car didn't have an idle problem before and now it does, you may have a failed IAC. More info please.

 

[ChrisCairns]

My thoughts were as follows....

Perhaps when I originally put the motor into the housing and it was halfway extended for instance, FAST would pick up that setting as the "default" and call that the zero count.

In answer to your question....it has idled reasonably in the past, then without any changes, suddenly idle too slowly. Not consistenly though to give me a handle on it.

Last night at the track for instance, at times I'd have to keep my foot on the gas to keep it idling. (At other times, it would be fine.) I looked at the Idle vs Coolant temp screen and the idle rpm line was much lower than where I had it set. I checked the throttle follower screen and it was much higher than where I had it set. And the minimum air screw appears to be correctly set. I.E. hasn't changed from where I originally set it.

I guess it's possible that the motor went south, but I don't hear of too many of these IAC motors going bad.

So hence the question...is it possible to reset the motor at "zero" when it's in the housing and I'll start again from scratch.

Thanks.

 

[norbs]

If the iac motor went bad it could have damaged the driver circuit. did the new iac move at all?

 

[Craig Smith]

Chris, it zeroes itself every time you cycle the power. I understand your question, and you do not have to be concerned about the FAST unit being confused where the IAC actually is. It rams the pintle into the seat every time it gets turned off so it is at zero on powerup.

Is the IAC count really high when the idle speed is too low? Does it sound like the IAC is wide open? If it is, and the idle speed is too low, either the TB is dirty and not letting air flow around the blades or perhaps there is a fueling problem causing the idle issue.

If it doesn't sound like the IAC is wide open, something is possibly wrong with the IAC motor itself, the wires that run it, or possibly the FAST unit itself. It's not a common problem to have a failure of the IAC driver, but it happens.

Check continuity from pin A to B on the motor, and then from C to D. Each one should be about 50 ohms. This is the resistance of the two coils in the IAC motor. Make sure that pins A or B don't have ANY continuity to pins C or D.

 

[ChrisCairns]

Thanks Gentlemen.

Good information Craig, on how the IAC and FAST work together. I'll check out the continuity this week. I did start the car today ... and it's idling fine again.

Stupid car.