I'd actually intended to respond to the original post, but forgot, so.....

The original post suggested rich running.  In my experience a too-rich
setup will tend to make the idle too high no matter what you do.
(Disclaimer: my "experience" consists of 18 years with my '81, so take it
for what it's worth.)

You can test your CO by utilizing a digital voltmeter and your O2
sensor.  If you're going to mess around with your car, you need a digital
multi-meter in any case; a $25 to $35 dollar meter will do fine and pay
for itself with its first use.

To set the idle mixture properly:

1) Get car up to normal operating temperature.
2) Stop engine, disconnect O2 sensor and connect sensor to volt-
   meter.
3) Start up car and look at volts generated by O2 sensor.
   Volts > .5 (like .7-.9) means too rich.  Adjust idle
   mixture until you get right around .5 volts being
   indicated.  You won't actually see a steady .5 volts,
   more like fluctuations above and below that.

If you can't get the mixture "lean" enough, then I'd say it's time to
adjust the spring in the AFM.  The procedures in the archives or pmail
me.

I think your idle rpms are probably within spec, but with the idle screw
adjusted all the way you should be able to knock it lower than that.

For over a year I had a high idle that I COULD NOT run down.  But, once I
got the mixture adjusted properly, no problem.

On Wed, 4 Mar 1998, The Martins wrote:

> I checked ECU (Digjet) and all as per Bentley, replaced all small vaccuum
> lines (although not the plastic ones or large ones from the aux air reg)
> Everything checked out ok and I'm still rich.  I can not check the CO2 from
> home and haven't brought it in yet to do that.  With the idle screw full
> in, it still idles about 8-900 rpm.  Is this normal?
>  Any other thoughts ?
> Can you buy a CO2 meter for home use?

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Tom Young               young@sherlock.SIMS.Berkeley.EDU
Lafayette, CA  94549    '81 Vanagon
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