Date:         Thu, 4 Nov 1999 01:15:03 MST
Reply-To:     CARY CHIANG <chiang1@USA.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         CARY CHIANG <chiang1@USA.NET>
Subject:      Re: [Re: Oxygen sensor: is a shielded wire necessary?]
Comments: To: vanagon@vanagon.com
Content-Type: text/plain; charset=US-ASCII

   Well, the O2 sensor wire on my '85 has a common-looking metal crimp
splicing the wire about 2-3 inches from the sensor itself.  I believe the Bus
Depot advertises generic sensors that have to be spliced that way in order to
make the connection, also.  How can that be if the wire is coaxial or
shielded?

Cary
   



EMZ <vw4x4@FYI.NET> wrote:
  Shielded wire is to prevent electrical noise from interfering
with the original voltage in the wire. VW didn't put a shield wire in
there for nothing. Running a low voltage, at a very low current, that
distance will surely have problems. The engine may still run. May
run rich, or lean, but only an emission machine will tell for sure,
as you drive down the highway.

            Eric                   86-VW4x4
            vw4x4@fyi.net          72-240z
            Pittsburgh, PA USA     1936-Chrysler


On Wed, 3 Nov 1999, karl wrote:

> Today I diagnosed a Vanagon problem I had never seen before. The customers
> van would start and run fine when cold, but gradually begin to run more and
> more rich (i.e. black smoke) as the engine temperature increased, and
become
> undriveable. After much swapping and testing of sensors, AFM's, ECU's, I
> found the problem to be a shorted out oxygen sensor lead. This being the
> large bright greeen wire from the ECU, through the harness, and to the
> oxygen sensor. The shielded portion of the lead is shorted out to the core
> of the wire, effectively shorting the entire OXS lead. I clipped the
> connection to the shielding, near the ECU plug (actually, inside the plug),
> and the problem is totally gone! NOW, the question: What is the actual
> purpose of the wire shielding, and will it be OK to leave it disconnected?
> Does the shielding prevent electrical signal interference? The other option
> is to replace the complete shielded wire, which could be a huge hassle
given
> that this is a Syncro. Any experts out there care to take a stab at this?
> Thanks!
>
> Karl M
>


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