The O2 sensor does give lower emissions than open loop.
If the motor goes lean, NOx emissions go up.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Tom Young
Sent: Saturday, September 20, 2003 11:30 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Not giving up!!!

----- Original Message -----
From: "John Rodgers" <j_rodgers@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, September 20, 2003 7:10 PM
Subject: Re: Not giving up!!!

> Andy Morse wrote:
>
> >    So why does the vehicle even need an oxs sensor if it runs OK
without
it?
> >I'm assuming it would run better? So should I spend the 80 bucks and
get
a
> >new sensor?
> >
>
> The O2 sensor provides the signal info that the ECU uses to aid in
> monitoring and controlling the engine and fuel injection to achieve
the
> lowest emissions possible. Without it, the engine runs richer, i.e.
more
> fuel burned so more pollutants into the air.

Well, not exactly.  A mechanically sound engine, well tuned, should meet
emission requirements and run at the stociometric ratio.  The O2 sensor
is
there the provide feedback to the ECU about the state of the fuel/air
ratio,
but it could as well be signaling to too-lean situation as well as a
too-rich situation.

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Tom Young                       '81 Vanagon
Lafayette, CA 94549         '82 Westfalia
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