Oxygen Sensor

[Huw Powell]

You should try cleaning the ISV (use carb cleaner, actuate it 
momentarily with a 9v battery each way a few times).

At rest it's about 1/3 open, which lets the engine run if it is broken.

The computer runs it whenever the idle switch is closed to let the right 
amount of air around the throttle body.

Test that switch as well, it's the one under the TB, a pair of the pins 
at the connector on top of the TB should read 0 ohms when the throttle 
is closed and open to infinite when it is just barely cracked)

Also, disconnect every electrical connection under the hood one at a 
time, clean, and reconnect using dielectric grease.

I hope this helps.

- Huw

PS, what year and model is it?

On 5/26/2015 4:00 PM, David Vanden wrote:
> I will put in an oxygen sensor.  Thanks for the advice.  On a separate
> note I just replaced the fuel pump and she is idling too high.  I tried
> adjusting the mixture but that didn't fix it.  Any ideas?  Decreasing
> the air on the throttle by setting the screw all the way to the right
> decreased it but not enough.  Any suggestions?
>
> David
>
> On Tue, May 26, 2015 at 2:54 PM, Huw Powell <audi at humanspeakers.com
> <mailto:audi at humanspeakers.com>> wrote:
>
>     Short term, for testing or diagnosing, it will run.
>
>     Startup will be normal, but when the engine gets to operating
>     temperature, the computer won't be able to manage the mixture properly.
>
>     Run without it for any length of time - like leaving home - can do
>     very bad things to the catalytic converter.  Fuel economy will also
>     suffer.
>
>     So first test if the OXS is working.  Then if it isn't, replace it.
>     Yes, I know, if this is a 4kq, it is *very* hard to get to, and it
>     will be rust-welded in place.
>
>     This might help:
>
>     http://audi.humanspeakers.com/timing2.htm
>
>     - Huw
>
>     On 5/26/2015 11:17 AM, dvanden46 at gmail.com
>     <mailto:dvanden46 at gmail.com> wrote:
>
>         Has anyone noticed if it is detrimental to the car or if the car
>         runs worse with the oxygen sensor disconnected?  This is for the
>         CIS E system.
>
>
>
>
>
>
>         Sent from Windows Mail
>         _______________________________________________
>         quattro mailing list
>         http://www.audifans.com/mailman/listinfo/quattro
>         http://www.audifans.com/kb/List_information
>
>     _______________________________________________
>     quattro mailing list
>     http://www.audifans.com/mailman/listinfo/quattro
>     http://www.audifans.com/kb/List_information
>
>