From what I understand these O2 sensors are comprised of a platinum cap
over a zircon tip. When heated, the fluctuating oxygen/co2 molecules of
combustion passing over the platinum creates an ion exchange between the
platinum and the zircon tip. This is read as a voltage - plus or minus -
depending on the molecule of the moment.This voltage signal is "read" by
the ECU and it's circuitry tells it what to do with itself in terms of
controlling fuel and air flow for mixture control.

In the pottery world where big gas kilns are fired, O2 sensors are use
to control the internal kiln environment to get a neutral, oxidation or
reduction environment. Each condition works on the chemistry of glazes
at high temperatures to produce spectacular results in the glazes. For
example, you cannot get a copper red unless there is not enough oxygen,
so the oxygen is deliberately reduced. If there is to much oxygen the
color will be green, not red. Cool stuff, working with O2 sensors for
pottery. Similar functions to the O2 sensors in our Vanagons.

John Rodgers
88 GL Driver
Chelsea, AL

Regards,

John Rodgers
Scott Daniel - Turbovans wrote:
> oxygen sensors last say, 5 to 10 years.
> 60,000 miles is getting up there.
> by 80,000 miles they're well used up.
> Every last vanagon there is that has an 02 sensor should be on its
> 2nd, 3rd,
> or 4th one.  ( like vanagon  engines - lol )
>
> They're very easy to check for output with a digital volt meter too.
> They're either OK, lazy, or dead.
> Scott
> turbovans.com
>
>
> ----- Original Message -----
> From: "Rob" <becida@COMCAST.NET>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Sunday, December 07, 2008 1:50 PM
> Subject: Re: oxs light came on
>
>
>> At  12/7/2008 12:26 PM, John Rodgers wrote:
>>> The O2 Sensor in the exhaust system, and the OX light in the panel are
>>> not electrically or mechanically connected. Once reset, you can
>>> drive  your van until the cows
>>> come home or the engine stops running well - which will happen if you
>>> don't change the O2 sensor within a reasonable period after the light
>>> turns on.
>>
>> I have never 'had to' change an O2 sensor in my life, I've swapped
>> them for Subaru conversions ands such but that's it. I do have a
>> Jetta that needs one, that will be my first 'have to' O2 sensor change.
>>
>> I wonder how many of you have 'had to' change an O2 sensor in a Vanagon?
>>
>>
>>
>>
>> Rob
>> becida@comcast.net
>>
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