lambarder o2 sensor?

Question

why does my lambarder sensor soot up causing rev and idleing problems yet works fine for a few days when cleaned

gordie yes cold and hot
also somtimes when engaging clutch somtimes the revs rise high

Answer 1

A sooty O2 sensor is a sign of either running far too rich or burning a great deal of oil, the latter being pretty obvious. Oddly, it might be the sensor itself that is causing you to run rich (see below)!

Once the O2 sensor soots up, it provides bad information back to the computer that will disturb its ability to properly control fuel/air mixture, ruining your engine performance. The worst of it is that this will typically make your engine run even *richer*, causing a bit of a 'death spiral' for the sensor, since running richer will create even more soot, etc etc etc.

You should have that sensor checked, or learn how to check it yourself with a high impedance voltmeter/multimeter. If the sensor is OK, you'll need to look for other reasons for the poor combustion that is causing all of the particulates in your exhaust that are fouling your sensor.

Also note that, depending upon your vehicle type, it may have *heated* sensors. If the heater dies, it'll take a while for the exhaust to bring the sensor up to temp after you start your vehicle, and in the interval, it's possible that you'll be running richer than necessary when you shouldn't be. That's another style of failure on these devices. Make/model/engine would have been *really* helpful.

What is this beast, and isn't it at least producing some sort of Check Engine light or something? A real O2 sensor failure usually starts to bring up codes, even on pre-OBDII model vehicles.
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Answer 2

You possibly have TWO lambda sensors working together with the injection system. A faulty 'upstream' sensor could cause the 'downstream' sensor to soot-up.

Answer 3

Do the idle and rev problems happen whilst the engine is cold as well as when it has warmed up?

Regards

Geordie