O2 sensor

[Ben Swann]

Brett is likely correct on this. Idle bounce is almost always due to the throttle body
switch or associated wiring.

Still it probably is not a bad idea to replace the O2 sensor - needs to be done someday
and the longer it is in there, the harder it will be to get out.

Just be prepared for a PITA job and be thankful if it come out without broken tools or
injury.  Use at least 1/2" drive - 3/8" will likely shear off.   The last one I did, I
had to break the casing off and pounded on a sacrificial 21mm 6 point 1/2" drive socket.
One of the 1/2" extensions sheared, then the NAPA breaker bar.  I finally got it out
with a MAP torch and persistance.

Have anticipated tools on hand and plan for worst - drilling out center just inside the
threads and retapping the hole using lawnmower plug tap - when you buy the tap then get
the correct size metal drill bit called for.  I have used this tap more than once so
consider it a good investment.

Ben

[Date: Sat, 28 Nov 2009 12:09:33 -0500
From: Brett Dikeman <brett.dikeman at gmail.com>
Subject: Re: O2 sensor
To: Hayes Myers <hayesmyers at gmail.com>
Cc: quattro at audifans.com, theringmeister at triad.rr.com
Message-ID:
	<9d9c4a330911280909n40f6fc81mcc0e992c70bd9b43 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

On Sat, Nov 28, 2009 at 8:33 AM, Hayes Myers <hayesmyers at gmail.com> wrote:

> Good point on o2 replacement. ?Car history: I bought ~1year/25000km ago
> ...afer it apparently sat ~4 years. (car has ~270km now). ?My ISV was
> cycling like crazy before I disconnected it ~5 months ago or more. ?I did
> some checking then and several folks (audiworld) had changed theirs and
> solved the cycling isv ?(well..engine was cycling up and down rapidly at
> idle...).

I'm 90% sure the above has nothing to do with the O2 sensor on a CIS car.

Among other things, if it does the idle ping-pong immediately (ie,
before the O2 sensor has warmed up), it's *definitely* not the O2
sensor.

If it has 60k+ since the last O2 sensor change, yes, it'll help with
mileage and emissions, but it won't solve the idle problems.

I assume you've checked operation of the ISV?  Have you run all the
CIS output diagnostics?

HTH,
Brett
]