Date:         Wed, 13 Aug 1997 16:30:55 -0700
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Erik Rhodes <ErikRhodes@platsoft.com>
Subject:      RE: Oxygen Sensor

Yup, passed, which is a thing to celebrate in any old VW, esp. in
California.  Thanks for the info.

> ----------
> From: 	Tom Young[SMTP:young@sherlock.SIMS.Berkeley.EDU]
> Sent: 	Wednesday, August 13, 1997 4:05 PM
> To: 	Erik Rhodes
> Cc: 	Multiple recipients of list
> Subject: 	Re: Oxygen Sensor
> 
> On Wed, 13 Aug 1997, Erik Rhodes wrote:
> 
> > 
> > 	I just had a smog check done on my '78 bus and the smog check
> > guy said the oxygen sensor was bad, thus misinforming the computer
> and
> > making the CO output too high.  Is this right?  Putting in a new one
> > hasn't affected engine running or anything, just what does this
> sensor
> > do?
> 
> The O2 sensor is a little battery.  The "potential" difference that 
> drives it is the difference between the O2 in the exhaust and the
> ambient 
> O2.  A "rich" mixture drives the voltage toward the maximum of its
> output 
> (around .9 - .95 volts) while a "lean" mixture drops the voltage down 
> toward zero.  The computer reads the voltage output and adjusts fuel 
> delivery accordingly.
> 
> Did you pass smog with a new O2 sensor?  If so, you were probably
> running 
> rich (and the faulty O2 sensor couldn't tell the computer about it) 
> which, if not too extreme, tends to imporve driveability.  So you
> might 
> not notice significant differences in the seat of your pants, but the 
> exhaust analyzer gives you a "pass" instead of a "fail."
> 
> ---------------------------------------------------------------------
> Tom Young               young@sherlock.SIMS.Berkeley.EDU
> Lafayette, CA  94549    '81 Vanagon
> ---------------------------------------------------------------------
>