Might be as simple as the accelerator cable not releasing to idle quite
enough when hot. Happened to me recently. Had the cable adjusted a tiny bit
on the tight side, so Backed off it and problem solved.

Daryl of AA Transaxle
425-788-4070
"On the cutting edge of Old technology"
86 Syncro Westy w/Turbo Zetec in the trunk

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
William
Sent: Wednesday, June 01, 2011 8:48 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Failed emission test

After all the years being on this list as a lurker, I have a minor
problem with my 1984 Vanagon.

I failed the first emission test because the idle RPM was above
1200 during the idle test.  The HC reading was only 56 and the
CO was only .24 during the high RPM test.  So I do not suspect
engine wear as the culprit.  Also the engine was completely
rebuilt in 1998 and I have put less than 50K miles on it.

This happened a few years ago and the problem disappeared after I
replaced the O2 and temperature sensor(not the dash sender).
So I replaced the O2 and temperature sensor yesterday.

This time, the idle RPM improved but was still flaky.  After
the high RPM test (2500), the idle RPM remained too high until
the accelerator was bumped.  And then the idle would slowly creep up
but not above 1200.  The emission test equipment was not happy when
the accelerator was momentarily bumped and it aborted the test.

Now I suspect the AFM.  Many years ago(15) I had idle problems
and the mechanic determined the spring in the AFM was worn.  He somehow
tensioned the spring so the spring applied more force.  This fixed the
problem until I replaced the AFM.

I am sure this problem and solution is in the Vanagon archive but
I honestly have never needed to search it.  I do not even know
where the archive is located.

If some kind person would direct me to the archive, I would be
very grateful.

Also, the Vanagon mechanic retired at Hans Wittler's Automotive and
now they do not service Vanagons.  Anyone in ABQ know of a good
Vanagon mechanic?

Thanks!

--
William
grateful@swcp.com

505 440 0760

Too many people spend money they haven't earned, to buy things they
don't want, to impress people they don't like.
-Will Rogers