-----------------------
Hi Dan,
    The oxygen sensor should be hot and providing the digifant with voltage
/ mixture signal    in about 2 minutes when starting a cold engine.  At this
point the ECU  will control the mixture based on this voltage.  It attempts
to keep the oxygen sensor voltage at 0.5 volts.  This is an impossible task
as the ECU  keeps correcting the mixture above and below the ideal mixture
resulting in the the oxygen sensor voltage bouncing above and below 0.5
volts.
    The oxygen sensors often go bad and cause rich mixture and / or rough
idle.  Several  list vendors have them for a pretty good price and they are
fairly easy to replace.  Use anti-seize compound on the threads.  You may
want to unplug the oxygen sensor for a short test and your van should run ok
but with a richer  mixture without the sensor.  It is best to have a CO
tester to adjust the mixture screw. This adjustment  only effects the idle
mixture and only  until the oxygen sensor is hot and the ECU takes the con.

Darrell Boehler
Makanda Illinois

-----Original Message-----
From: Dan Hall <Spitzwagen@AOL.COM>
To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM>
Date: Sunday, August 02, 1998 8:55 PM
Subject: mixture adjustment without gas analyzer

>Volks,
>Is there any way to make improvements in the mixture without an exhaust gas
>analyzer?  Just something in the ballpark until I can get to  a mechanic.
>Also, which way do you turn the CO content screw to lean or richen the
>mixture?
>I tried searching the archives but, as usual, didn't have any luck.  Are
the
>archives as slow for you guys and gals as they are for me?
>Thanks
>Dan Hall
>Tuscaloosa, Alabama
>'86 Westy
>