New to Audifans, 1991 Audi 80Q, bad O2?

[Shawn Kubik]

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Hello all, I've spent some time at the Audiworld forums but not here yet, so
I just fired up outlook, set up some rules and got the list going, I have a
question about my O2.



A few weeks ago Bosch P/N 13913 was installed, ran fine for a week or so but
then began cutting real bad, pressing gas pedal did nothing, but could
always restart quickly and would wait 5 seconds until the symptoms came back
whenever car went into closed loop and started monitoring O2 output (would
be ok on a cold start till it warmed up for a little while), I learned that
unplugging the preheat connector under hood would cause the problem to
immediately disappear but getting into the problem further, I noticed for
some reason that the preheat isn't optional for me, after driving for 15
minutes without preheat connected it still wouldn't throw anything but .5v
telling me it wasn't hot enough yet.



So, frustrated, I left it unplugged for a week or so and then decided to
plug it back in, to my surprise it kept running, no problems, the sensor
reported normal .2 - .7v fluxuations and I thought it was just a thing that
occurred due to me running some seafoam through the intake manifold, figured
the sensor was clean again now and all was well.



Well, it was ok again, for about another week.. Drove a few miles and sure
enough, bogged hard back down to 200rpms, so I popped the hood and yanked
the preheat again, runs noticeably richer again but it keeps running with
preheat disconnected.  To investigate further I checked continuity between
the preheat & signal on both the sensor & ecu harness sides and verified the
O2 sensor was wired properly.



So, have I learned that the sensor is officially bad and the preheat is
either short circuiting to the signal lead inside the sensor/the sensor
throws wrong voltage intermittently when heated or is something else causing
the problem?



I'm going to order a replacement O2 sensor from TPC tomorrow but I've been
worried about it, thinking that it would be pretty uncommon for a bran new
O2 sensor to be intermittently bad like this.



Thanks guys, I can use a universal Bosch 13913 in my car right?

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