Date:         Wed, 31 May 2000 09:41:38 -0700
Reply-To:     roger.bowman@GULFAERO.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         roger.bowman@GULFAERO.COM
Subject:      (no) oxygen sensor heat
Content-Type: text/plain; charset=us-ascii

After some rather difficult drivability troubleshooting, I have discovered that
my Oxygen sensor is not getting any heat. (from the harness, that is...)

My '90 syncro Westie exhibited some cold and cool start drivability problems;
stumbling, no power and idle falling to zero.  Symptoms could be alleviated by
turning the ignition off and then back on, or re-starting the engine.  Using Mr.
Fluke's meter showed the oxygen sensor putting out a signal that would start
around .7 v, and then slowly falling, mirroring the engines slow fade to stall.
Replacement of the oxygen sensor showed no relief.  Once the sensor appeared to
warm up, the engine would run as good as ever, and the sensor displayed the
proper crossover behavior.  As near as I can tell, the sensor is not getting
warm enough until several minutes (2-3 after cold start, getting progressivly
shorter as the "restart" gets "hotter".  Insulating the sensor improved this
behavior but did not correct it.

Mr. Bentley sez that the 2 conductor plug (Ox Sensor heat) to the sensor should
show 12 volts when the ignition is on, and mine does not, which leads to my
question.

Does anyone know where (specifically) the oxygen sensor heat plug gets power
from?  The manual is not particularly clear, and the wires all disappear into
harnesses that run hither and yon; a breif visit to the power side of the
Digifant Relay shows power at that location, but making the leap from that point
in the harness to the ox. sensor....well, I am puzzled.  Where is that faint
horizontal line connection shown in Bentley actually located so one may examine
it and verify its continuity?

Please reply to me directly; I am currently "Off List" while I get up to speed
at my new job; Environmental Manager at Gulfstream (talk about custom
interiors...).

roger.bowman@gulfaero.com

Thanks in advance for your locational advice...

Roger Bowman

'90 Syncro Westie - white