IAC longevity problems

[Bruce Plecan]

-----Original Message-----
From: MJones <rmjones at cyberhighway.net>
To: 'diy_efi at efi332.eng.ohio-state.edu' <diy_efi at efi332.eng.ohio-state.edu>
Date: Friday, August 14, 1998 3:41 PM
Subject: RE: IAC longevity problems


The below is referenced to my gm knowledge.


>Is it critical, then, that the IAC never be allowed to reach the ends of
>its travel?

In his reference to it being like a gm, you can unscrew the pintle from the
motor, at full travel.

  What happens to the IAC motor if the throttle blades are set
>such that the idle rpm can't come down into control range?  The IAC would
>go full closed.
  Would the IAC motor be damaged by this?

Fully, no, just shy of there, maybe, if improperly machined, yes.

 Similarly, the 4D
>opens the IAC a fixed amount during each start sequence.  No matter where
>it was when last operated, it opens it further.
 What happens to the motor
>if, when tuning/adjusting etc. you crank the engine over several times in
>succession but never start it.  The IAC goes open further each time until
>reaching the end of its travel.  Would this damage it?  If so, how does GM
>handle this scenario?

Different strategy completely, gm doesn't keep retracting the IAC.
>
>Beginning to sound to me like the closed throttle angle must be set such
>that the IAC does not go full closed

why do you say that?.

, and that the IAC be disconnected
>during fiddling.  Any other ideas?

When setting min idle the IAC is supposed to be unplugged, on the gms.

Cheers
Bruce
>
>Mike Jones
>
>
>
>Bruce Plecan wrote:
>
>
>
>Sounds like the distance from the mounting "face" to the orfice is
>too great allowing the pintle to be hyper extended, and too much of a load
>for the stepper motor.    Might try to find out how to extend it,
>installed, and record that lenght, and compare it to someone else's
>That's all I can think of.
>Cheers
>Bruce
>
>