CIS-E air by-pass

[Ti Kan]

Kurt Deschler writes:
> 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
> >
> > 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.
> >
> 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.

I know that on many CIS-E3 systems the idle screw on the throttle body
is supposed to be closed completely.  The ISV should handle *all* the
air bypass chores.  If you were to open up the idle screw you will not
be able to achieve optimum ISV operation.

-Ti
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