Re: Oxygen Sensor

[ti@amb.org (Ti Kan)]

River6822@aol.com writes:
> I installed the Bosch 3 wire oxygen sensor in my 88 80q. I spliced it into 
> the old electrical connector with water tight crimp connectors. The 
> connection is sound (triple checked).
> 
> The car has lost power and is now backfiring slightly. Could I have a bad 
> sensor ?

Possibly a bad sensor, but it's also possible that the basic CO adjustment
is out-of-whack.

> How can I test it ?

Try running the car ay idle without the OXS sensor connected.  Meansure
the sensor's output voltage relative to ground with a digital voltmeter.
There should be a fairly steady voltage, somewhere between 0.2 and 0.7
volts.  Now connect the sensor and measure the voltage at the sensor
again, it should now fluctuate up and down in that range.

To adjust basic CO mixture you should consult the Bentley manual for your
car.  Each model has its own unique quirks about whether certain vacuum
lines should be disconnected and/or plugged, and what the settings should
be, etc.

> Does it matter if the white wires are swapped ? (I tried them both ways but 
> the car runs the same.)

Those are just leads to the heating filament in the sensor, and there
is no polarity.

-Ti
96 A4 2.8 quattro
84 5000S 2.1 turbo
80 4000 2.0
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