Yes, the O2 sensor is in the CAT. It does seem an unlikely placement as
majority of other vehicles (mainly domestics) have it located further
upstream on the exhaust manifold. With the O2 sensor further downstream, its
more susceptible to incorrect readings due to leaky exhaust systems. This
happened on my 87GL - I had a hole in the bent pipe just before the CAT and
the sensor was sending wrong signals (sucking air through the hole) to the
computer resulting in severely reduced engine performance. I changed the
pipe/gaskets and it was fixed.

Ken Madsen
Toronto, Ontario
87GL

-----Original Message-----
From: Jeremy Speer [mailto:jspeer@POBOX.COM]
Sent: Saturday, May 18, 2002 11:08 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Where is *your* O2 Sensor?

Folks,

On my '89 Westy, my O2 sensor is screwed into my catalytic converter. It's
attached just beyond where the exhaust pipe connects to the cat.

Uh, is this correct? I thought it was supposed to be further upstream, maybe
at the collector junction.

Am i being dumb, or is something amiss here?

As always, thanks.

-jspeer

'89 Westy, "Mystery Machine"