At 02:48 PM 6/10/2001, Mike Finkbiner wrote:
>There were none.  After the engine was fully warm, the voltage sat at a
>steady .8 V no matter where I had the adjustment screw, up to a full five
>turns in or out from the base position.  There didn't seem to be any change
>in the engine idle,or at 2000 RPM.

Which means that you're still running rich.  The sensor has an absolutely
*tiny* range, so the slightest bit rich or lean will drive it to one side
or the other.

>Remembering that someone had suggested that the O2 sensor could be coated
>with soot, and be reading rich, I removed it.  It was indeed coated with a
>rich black soot, so I took a torch and heated it up.  The metal came up to a
>cherry red very easily, and after it cooled off, the black coating was gone.

Coated because you're running rich...

>I re-installed it, and re-tested.  The results were identical.
>
>In the interests of experiment, I left the adjustment screw turned out 5
>turns, assuming that if the engine were running rich, that might help.
>Driving around town, it seemed to make no difference.
>
>Is it possible that the O2 sensor is shot?  It's only a year old, and on the
>Digitool, once it's up to temperature, the readings swing between a bit
>negative and .8, so something is certainly changing.

So it's working ok in closed-loop mode.

>Was I testing incorrectly?

I don't think so.

david

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"