If your O2 sensor relay does not work...

[smcdermott326]

What will be the symptoms of the relay not doing it's job? Poor fuel economy or is there more to it?

[AlpineIS]

A relay operates much like a switch. If it is not functioning, the 02 sensor will have no current flow and will not operate. A faulty or non-operational O2 sensor will cause the engine to run rich (more fuel), which in turn will hinder fuel economy.

[jlevie]

I sort of think that relay is only for the O2 sensor heater. If it is bad it only delays full operation of the O2 sensor.

[AlarmedBread]

When mine was going bad.

CEL at idle, blip throttle it goes away, no CEL from 1500-2900, at 3000 the engine would cut out, stutter, CEL, then rev up again with the CEL flickering.

It was running very rich and falling on it's face from nearly flooding as best I could tell.

[328ijunkie]

What if i have the CEL at idle, blip (with severe hesitation) and it goes away and stays away... Same thing?

[Mike325]

It is possible that it is the same. One other way to tell if your o2 is bad is to smell the exhaust. It would have a rich sulfer kinda smell to it if it is running rich.

[328ijunkie]

I dont have the sense of smell :( and my exhaust exits somewhere under the car for the most part anyway :(X2

[nando]

the relay is only for the heater circuit. without it, the sensor will take longer to warm up, and possibly not operate at a hot enough temperature during low load cruising and idle - the result is it won't be as accurate and possibly wear out faster.

[328ijunkie]

Yeah well i get a CEL at idle and poor off idle performance so... Im thinking thats my issue, that or the O2 Is dead all together...

[hendrixvodu]

im having a prob with mine....when mine is plugged in the car bucks very badly and cant idle at all....but when i unplug it the car runs fine???? any idea what that could be??????


and its a new sensor

[Farbin Kaiber]

im having a prob with mine....when mine is plugged in the car bucks very badly and cant idle at all....but when i unplug it the car runs fine???? any idea what that could be??????


and its a new sensor

My 85 318i did the exact same thing. My solution?............



















Yank the m10 and prep for s52. Hope this helps.

[328ijunkie]

Haha S52 FTW. Could be a bad connection or bad relay. When its unplugged the ECU just runs in open loop which is bad for fuel economy but yeah.

[hendrixvodu]

My 85 318i did the exact same thing. My solution?............



















Yank the m10 and prep for s52. Hope this helps.

oh shit my s52 is on layaway .......damn sears!