Testing O2 Sensor

[britt911]

My 86 Carerra is running unbelievably rich. Horrible gas mileage (even with my foot off the gas). I suspect the O2 sensor is going bad. Is there a way to test it before popping for a $220 test?

Thanks in advance
britt

[stlrj]

02 sensor will not make your engine run that rich but an easy test: unplug it and see if it makes a difference.

Joe

[RickM]

A Bosch generic replacement shouldn't be more than $60-$80. A search will yield lots more info.

[Bill Verburg]

Check the voltage there are 3 wires, black is the sensor signal which should fluctuate between 0.1 and 0.9 Vdc

If you connect in the harness it is the green wire.

[Early_S_Man]

Don't just hang any old meter or test lamp on that O2 sensor wire, either!!! The test instrument MUST have 10.0 Megohms or greater input impedance ...