I am experiencing poor gas mileage with my 940 sedan. I'm getting about 21 MPG with >90% freeway driving @ 60mph.

I checked the codes and there was a fault that said the engine was running rich/lean, so I thought I would check the 02 sensor. I read all of the information about 02 sensors in the archive and I thought I was ready to check the sensor with my voltmeter. However, I can't find the spade connector where the voltage is measured. The only wire that appears to come from the exhaust ends in a 3 pronged connector that has a small wire retainer to hold it together. Can anyone tell me another way to check if my 02 sensor is working? Or does anyone have a pic of the wire that I need to check?

Thanks for any assistance!

Doug

That's it. I just ran a check on my own. Is your car LH Jetronic or Rex/Regina? Mine is LHJ so the wire colors I refer to may not match yours if it is Rex. In fact, the Rex sensor is completely different from the LHJ, they are not interchangeable.

The LHJ O2 sensor has 3 wires coming from it bundled into 1 cable, 2 wht & 1 blk. The wire you want is the black wire which is the signal (the 2 wht wire are for an internal heater). I checked mine by removing the sensor and measuring the voltage it produced while being heated in a MAPP gas flame (propane will work too). I just had to disconnect the cable and measure the voltage across the metal body of the sensor and the black wire. If you are going to test it using another method, you can safely expose some of the wire as long as you tape it up afterwards to keep out contaminants. It may also be possible to run your probe into the connector itself to make contact with the wire (not always possible as some may have a sealant filling the holes).

I like the way I measured it since it is disconnected from the ECU, the ignition is off, and I really can't screw up any ECU inputs if I'm careless and short something out.
--
Bob Kraushaar '94 945T, '88 240, '84 242Ti, '94 F-150 (deceased), '88 300 TE, '89 560 SL, '68 Shelby GT-500 KR

RJK,

Thanks for the help. I am not sure what ignition type is in my car, but I think that I will expose some of the signal wire and check the voltage. This seems like the easiest way to get a reading without having to go to the work of removing the sensor (have to get to work in the car on Monday!).

Thanks again for the suggestion. Best wishes,

Doug