Idle screw on NG engine (actually more CIS/ISV now)

[rob hod]

    I think you've still got to adjust the idle screw properly as far as
getting a correct basic setting is concerned, - i.e. one which approximates
on its own to a normal idle on a warm engine. Although I'm only familiar
with ISV systems rather than full blown ECU control, it seems that any
auxiliary air device that is 'shut at rest' could do little about a
situation where the basic idle setting is too high and flows *more* air than
needed.  On the other hand a basic setting that was too low would mean that
if your stabilization system took a dive for whatever reason you would be
faced with a non-idling car.

     On a well tuned ISV car you should be able to disconnect the ISV plug
at idle and have the engine dip in revs but keep running. (You'll probably
have to stop and restart the engine as well as reconnect to get the ISV to
kick back in, and I've never done this on an ECU controlled system, so don't
try that one at home kids)


rob
----- Original Message ----- >
> Message: 3
> From: DGraber460 at aol.com
> Date: Wed, 10 Apr 2002 16:39:56 EDT
> Subject: Re: Idle screw on NG engine
> To: one at humanspeakers.com
> Cc: quattro at audifans.com
>
> --
> [ Picked text/plain from multipart/alternative ]
> In a message dated 4/10/2002 1:49:23 PM Mountain Daylight Time,
> human747 at attbi.com writes:
>
>
> > The ECU controls the air via the idle stabiliser valve.  The 87.5 Coupe
> > GT NG setup still has a "legacy" idle screw - which is not even present
> > on the later NG's.
> >
>
> Absolutely right. Forgot about that dastardly ISV unit. I've been living
> under the URQ hood _too_ long.
>
> Dennis Graber
> Denver
> "Good judgement comes from experience, and a lot of that comes from bad
> judgement."
>