E30 325i, Cat replacement pipe and lambda sensor

[joeyb]

Hi,

Quite a while ago I swapped out my Cat equipped front and centre pipes (2 piece system I think). I replaced it with a non cat equivalent and just left the lambda sensor loose in the engine bay still plugged in.

The car seems to run rich, would the fact that the sensor is plugged in but not present in the exhaust be a problem?

Should I trace it back to source and unplug it? Is that possible?

[Brianmoooore]

Yes, the sensor needs to be disconnected (under the battery tray). If the built in heater is getting it hot enough to operate in the absence of exhaust gasses, it will be responding to atmospheric oxygen, and adding fuel in an attempt to use it up.
The CO level will also need checking/setting and adjusted if necessary by the screw on the side of the AFM.

[joeyb]

My mate prodded it in the engine bay whilst I was sorting something else and he mentioned it was hot... That's what prompted me to ask here. I'll get it fully disconnected.

Thanks Brian.