CIS-E air by-pass

Kurt Deschler desch at
Thu Aug 26 22:43:11 EDT 2004

That procedure works fine with the ISV hooked up. You are simply 
minimizing the ISV correction through successive approximation. The only 
model specific part is the idle rpms. Not everyone has the Bentley of the 
special tools required for the "correct" procedure.


On Thu, 26 Aug 2004, Ti Kan wrote:

> Kurt Deschler writes:
>>> Can someone give me a definite answer on if the "idle air by-pass screw"
>>> (side of the throttle body) should be turned in all the way to the stop?
>>> Or should it be unscrewed 1-3 turns?
>> The air screw should never be turned in all the way. To adjust it, you
>> need to listen how the engine winds down to idle from 2500 rpm or so. If
>> it dips under the target idle (~900 rpm??) when you release the throttle,
>> then you need to unscrew the air screw some. If it hangs above the target
>> rpms then slowly creeps down, then you need to turn the screw in. Take if
>> for a short drive, stopping to make any fine adjustments will yield a good
>> idle. Make sure that o-ring on the screw is good before trying to adjust
> Kurt,
> This is car and engine specific.  What you're describing is contrary
> to the function of the idle stabilization system on some models.
> The Bentley manual for the appropriate model should be the definitive
> guide when it comes to adjusting the idle, CO mixture, and ignition
> timing.
> -Ti
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