In a message dated 98-06-09 20:11:07 EDT, raven@HALCYON.COM writes:

<<
 The engine does not seem to be running rich. Tailpipe deposits are dark
 gray, not black. Went for emissions testing today, passed with flying
 colors. HC was 8ppm at idle and at 2500 rpm, better than my test a year ago.
 HC would be higher if van was running rich, right? CO readings were also
 lower--at idle CO was 0 ppm. Does this seem odd?

 O2 sensor is working and is not grounded or anything. I can attach a
 voltmeter and watch it do its thing as the ECU adjusts mixture.

 Another variable I neglected to mention is that I installed a new
 syncro-style air filter when I did the tuneup. The old air filter was also
 the syncro style.

 That's all for now...

 Mark McCulley
 87 syncro Westfalia
  >>

 Mark, what matters is what are your CO readings before the CAT. That little
plug before the CAT is where the exaust sample is taken for adjusting the fuel
mixture. Your emessions test wont really show a rich mixter because your  CAT
will clean most of the exaust up, since they are sticking the exaust probe in
after the CAT. Find yourself a vanagon specialist and ask few questions. Talk
to other vanagon owners in your area. The syncro air filter has nothing to do
with your problem.
 Michael Modl. 87b syncro.