N14 JCW, 128k miles. I'm tracking the car every couple month.
Started to feel a bit more sluggish on my butt dyno, so thought I'll put a new downpipe on. While doing that I obviously removed the O2 sensor.

My O2 sensor was covered in black carbon. Compared to my other Mini, it's quite different. The other one is more brownish.


I had no CEL. Does that look normal or is it running rich? Any suggestions what to look at, or is the O2 sensor responsible for the richness?

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That looks much more black that I would have expected. What is the condition of the plugs? Coils? How has the car been running otherwise? Do you have a tune, or are you still stock tune?

 

Thanks! Ordered a new O2 sensor to see if it that one is on its way out.

Not sure with the plugs - haven't taken them out, but will do tomorrow. Good point. A good plug I can easily spot

I ran an Alta Accessport tune for maybe 100miles on street, but it throws a P2885 on the track. So right now it's a stock tune. I realized that I have a paper filter in the air box instead of a K&N. Not sure if that would do that though.

 

I believe this looks fine. Some deposits on the ground electrode and the tip looks a bit burnt. They ran maybe 4k miles with a few track days (maybe 6 or so).

 

Looks like wet oil on bottom of those threads ??? ( Valve cover gasket kit needed, may need replacing if that is wet oil )
Looks like the begining of ash deposits forming ? ( speckles = burning oil ) But if in there for 40K miles or more I wouldnt lose sleep over it.
Maybe do next change at 30K and re-asses.

 

Have you checked the Turbo's wastegate vac line ?

 

An issue with the vac line would probably throw a CEL on the stock map as well I believe. The AP issue comes up in older threads quite often, so probably just normal.

I'll for now just throw money at it with a new O2 sensor and re-check in a few month.

Since the plugs look normal, maybe it's just old.