An easy way to diagnose if a mixture problem is due to the O2 sensor is to
turn the ignition off and back on while the engine is still turning. If the
problem clears for 30 seconds or so then the O2 sensor or wiring is the
problem. Also try full throttle (assuming the full throttle switch is
working). If you suddenly get the burst of power, again back to the O2. The
most important ground connection for the O2 is the brown wire that goes
through the distributor harness. If it is connected to the engine at one of
the oil breather tower screws, move it to something metal on both sides.
Check the ring terminal carefully. The crimp can look good but that corroded
wire makes for a lousy connection. New ring terminals with the heat shrinks
ends will work wonders.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
David Clarkson
Sent: Tuesday, May 26, 2009 11:04 AM
To: vanagon@GERRY.VANAGON.COM
Subject: intermittant rich running problem

Just a follow up to the previous post. The oxygen sensor voltage seems to
be swinging between .1-.7 volts with the engine warmed up. Thanks for any
help  that you can offer fellow vanagonauts.

David

In a message dated 5/26/2009 10:34:31 A.M. Eastern Daylight Time,
Dvdclarksn@AOL.COM writes:

I'm  having an intermittent rich running problem with my 90 2.1 liter
Westy.
This was the same symptom that I had that was fixed 13 mos. ago with  a new
temp  II sensor. This has been replaced with no effect. One  other
interesting thing  that I noticed when attempting to install a  wire to
feed an oxygen
sensor  monitor was that just connecting an  additional wire to the sensor
causes an  immediate rich running  condition. I had a problem this morning
when the engine  was started  cold with running rich also. Am I looking at a
problem involving   cleaning up some grounds again. I'm thinking that I may
also
need to test  the  voltage coming from the sensor and also at the ECU. Any
ideas  towards diagnosing  this problem would be greatly  appreciated.

David  Clarkson
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