Idle Problems

[Bernie Benz]

You may well be right Brett, inasmuch as I've not had such a problem with
the 200-20V idle system, so have not delved into it in detail.  But from my
exp with the 7A idle system, there should be no way that idle speed could
ever fall below the preset TAB (throttle air bypass) hot adjustment of
approx. 700 RPM.  That is the purpose of the TAB, i.e. to set a minimum
threshold hot idle speed, above which the ECU controled ICV is in control.
The components are different, but the intent is identical.  IMO, the TAB
adjustment and the ICV need checking.

Bernie

> From: Brett Dikeman <brett at cloud9.net>
> Date: Sat, 15 Jun 2002 23:05:52 -0400
> To: Endr‘di Gábor <Gabo at maffia.hu>, 200q20v at audifans.com
> Subject: Re: Idle Problems
>
> At 12:08 AM +0200 6/16/02, Endr‘di Gábor wrote:
>> Hi Audi Fans!
>> I've a problems with my 20VQ
>> Symptoms:
>> After some really hard accelerations the idle speed falls down to 200
>> rpm, -sometimes the engine stops- and after it the idle speed starts
>> to raise up to 900.
>
> The stalling is a dead giveaway for a toasted turbo bypass valve.
>
> I would check both the control line(which runs from the valve at the
> front of the car right in front of the turbo to the back of the
> intake manifold) and the valve(remove from car, apply moderate
> vacuum, make sure the valve holds the vacuum.)
>
> I believe that control line failure does not cause the stalling, only
> a leaking valve does...but I'm not sure.  In any case, the line is
> probably shot too; it usually only lasts a few years tops because of
> the heat from the exhaust..more specifically, it seems to fail right
> around the wastegate area.
>
> Brett
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