IAC

[James Patterson]

** Reply to note from dn <dn at dlogtech.cuc.ab.ca> 02/05/96 11:47am MDT  

> Dan wrote:
 
> The IAC is a stepper motor controlled by the ECU.  The ECU stores a reference
> position when the engine is shut off, and closes the valve so it knows where
> it is on start up (open loop, no position feedback from the IAC).
> 
> I don't know for sure if you could just bypass it, I think it is necessary
> to have it hooked up in order for the engine to get enough air at idle.  Can't
> remember if there is a separate idle speed screw on the throttle body.  You 
> could maybe adjust the thing by removing it and rotating the pintle until
> you get the idle speed you want, and just leave it there, but you won't have
> any warmup fast idle or other compensation.  You might also be able to hack 
> off the motor end of the thing, so you can rotate the shaft and have a manual 
> adjustment 

It would be simple enough to put a 3 position switch (on-off-on) wired into the  
IAC to manualy control speed.  The voltage ( I believe 5v) would have to be  
supplied.  The switch could be mounted in the cabin and allow the driver to  
adjust for various conditions.  The IAC holds its last position so you should not  
have to adjust at every startup.


James Patterson
james at uclink.berkeley.edu