That was my problem with my 84 westy after the wire was fixed by Sonoma
Volks my MPG increased from 10 MPG to about 25 MPG's
-----Original Message-----
From: William Dummitt <williamd@COMPUSERVE.COM>
To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM>
Date: Wednesday, June 03, 1998 6:35 PM
Subject: rich running van SOLVED! thanks Gerry S.

After many, many hours of fruitless troubleshooting, parts swapping,
cursing, poking voltmeters into circuits, etc. I finally found the reason
why my 87 syncro would run rich no matter what I did or what I replaced.
Gerald Skerblitz, our former listmaster, pointed out that the oxygen sensor
wire was coaxial in nature- it is a layer of green  plastic insulation over
a grounded wire sheath, over another green insulation layer, with the wire
that carries the small (0-0.9v) oxygen sensor current in the center.  Some
long-ago mechanic had replaced the spade connector by simply crimping a new
one on, and had both the grounded sheath and the center wire under the
connector, effectively grounding out the oxygen sensor circuit, regardless
of whether the sensor was connected or not.  While I have directed many an
expletive at this unknown person, that actually was an easy mistake to
make-it takes a careful examination to discern that this particular wire is
different than most of the others in the system.   This apparently makes
the ecu dump in more and more fuel, causing the symptoms I described in my
previous post.  Simply cutting back the grounded sheath half an inch and
crimping a new connector to the central wire solved the problem- the van
immediatly started running great, in spite of low compression in a couple
of cylinders.  Small things are so important with these systems!  Special
thanks to Gerry and to the many other people who pointed out a whole slew
of facts I didn't know about the digifant fi.

Bill
www.geocities.com/yosemite/gorge/1706