Could it be the O2 Sensor?

[SJ]

Try this site for DIY oxygen sensor testing. The method works, I test my new
oxygen sensors before I put them in.
http://www.mr2.com/TEXT/O2_Sensor.html

This is from a post of mine when I had Oxygen Sensor problems.
= = = = = = = = = = = = = = = = = = =
Huw wins the fair maiden for his correct diagnosis - -> defective Oxygen
sensor.

The problem was the oxygen sensor. I had to drop the catalytic converter to
get at the oxygen sensor. Of course, the cat hardware was replaced with
Stainless Steel, ala Huw.

There was a dramatic difference in performance after installing the new
oxygen sensor. Car had lots more Ooooomph! The old sensor looked pretty
ratty. I think it was the original sensor(100K plus miles).

With the new oxygen sensor , the sensor voltages and fuel regulator current
readings are:

Ignition on    -  reg current at 100ma, O2 voltage at .5v (This voltage is
provided by the ECU)
Start            -   reg current at 70ma, O2 at .6v
Warmup       -  reg current steadily drops to 3ma , O2 voltage stays steady
at about .7v - then starts swinging between .2v and .9v as system goes into
closed loop mode. Time to closed loop was about 3 minutes.

I found an article at       http://www.mr2.com/TEXT/O2_Sensor.html     which
explains how to test the sensor on the bench. I tried the technique and it
worked. I tested the new sensor before installing it.

I paraphrase the article below:

1. Clamp O2 sensor in vice, attach digital DC voltmeter to sensor. Gnd to
sensor body, Pos to black sensor lead.
2. Propane torch set to high, heat perforated sensor tip - - should see at
least .6V within 20 seconds.
3. Remove heat - - voltage should drop to under .1V within 4 seconds.
4. Heat for 2 minutes and watch for drops in voltage.
5. Move the flame back and forth over the sensor - voltage will quickly
change from high to low.

Test Summary: Any sensor that generates 0.9 V or more when heated, show 0.1V
or less within one second of flame removal, and pass the 2 minute heat test
is good regardless of age.



SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q



>
> Message: 4
> Date: Wed, 26 Nov 2003 11:14:43 -0700
> From: Zsolt <zsolt1 at telusplanet.net>
> Subject: Re: Could it be the O2 Sensor?
> Cc: quattro at audifans.com
> Message-ID: <3FC4ED93.3000906 at telusplanet.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> speaking of which...is there a way to test the O2 sensor itself?
>  TIA, Zsolt
>