Emile

[Emile]

How do one search for “o2 sensor” if a minimum of 3 characters is allowed? Anyways what are the symptoms of a bad o2 sensor?

Thanks
1995 m50 525i Manual 200000km

[Bill R.]

How do one search for “o2 sensor” if a minimum of 3 characters is allowed? Anyways what are the symptoms of a bad o2 sensor?

Thanks
1995 m50 525i Manual 200000km

[Emile]

mmm thanks

[billb]

How do one search for “o2 sensor” if a minimum of 3 characters is allowed? Anyways what are the symptoms of a bad o2 sensor?

Thanks
1995 m50 525i Manual 200000km

Poor mileage. Check Engine light. Poor running. Excessive sulfur smell from catalytic converter (maybe).

I'd replace it at 60k miles regardless of what the books say (100k normally).

Bill B.

[Emile]

South African models not sold with engine check light – not even in ’95 – Error codes is obviously the place to start but just one question – can o2 sensor/s be bad without an error code?

[GS535i]

How do one search for “o2 sensor” if a minimum of 3 characters is allowed? Anyways what are the symptoms of a bad o2 sensor?

Thanks
1995 m50 525i Manual 200000km


Open the O2 sensor connector, and with a Digital Multimeter, bridge the sensor output to ground through the meter when set on a low DC voltage scale 9 of the 3 wires, 2 are for the sensor heater, the 3rd being the output): With the engine up to temp and running, the voltage should be in the 0.2 - 0.8v range, ~ 0.5 being ideal. Squirt some WD-40 into the intake to drive it rich, and the voltage should respond upwards. Conversly, open a vac hose,and the lean condition will drive the O2 voltage down.
If any of this happens, the O2 sensor is OK!! ;)

[winfred]

if you don't have a ce light are you sure your car came with a 02 sensor? to do a useful test on a sensor you really need a graphing meter and a propane torch, i find the sensors hardly ever totally die they just get slow, the injection system when not at full throttle constantly swings from lean to rich, when the sensor's reaction time gets slow this throws off the computer. how i run the test, get the sensor in a vice and hit it with the torch while watching the readings, with in 25 seconds it should be over .750mv dc, it should remain over .850 mv dc with the torch pointing at one of the slots/holes of the sensor, now for the part that a graphing meter is helpful on, after about a minute and a half of full heat when you take the torch off of the sensor voltage should drop to near 0 in about a tenth of a second. the two white wires are the heater, check these for contineuity, if open the heater and the sensor is dead, the black wire is the signal, this is the one you hook the red meter wire to, now for the ground, if it's a a 3 wire sensor hook the black meter wire to the body of the sensor, if it's a 4 wire unit hook the black meter wire to the gray sensor wire