Hi,

I've searched the forums and am looking for confirmation on what I've found. I have a 2015 MINI Countryman S ALL4 with under 22k miles.

In colder temps, I'm experiencing a rough idle accompanied by a strong exhaust odor. It is visible but seems to be more than just water vapor. My exhaust pipe tips are covered in black. In addition, there is a faint hint of gasoline.

It does not exhibit these traits when the weather is in the 60s. It does when the weather is in the 40s.

I've seen that some people with these symptoms have had problems with their fuel pump and/or carbon build-up.

I plan to call the dealer about this but want to have the most accurate information to give them so I don't send them down the wrong path.

Thanks, in advance, for your help.

 

does it do the same when the car is warm/warms up? any CEL?

 

No check engine light. Yes, after warm up but not sure if it does after a longer drive.

Thanks!

 

Do you still have the original spark plugs? If so, take them off and see how they look, color and gap wise. Basically, your car isn't completey burning gas and the cat is still cold to burn the unburned gases. That is my theory :-)

When my CMS was rough and wont even rev pass 2k and somtimes it shuts off, it turned out that the spark plugs gaps were tooooo tight. And it had 25k on it.

 

Thanks MiniToBe.

I just got an update from my MINI service advisor. What is happening is by design. When the weather is cold (especially when the previous day was warmer), the car runs richer on startup to try to bring the engine to temperature more quickly. That excess fuel does not burn completely. Then, once the catalytic converter warms up, the fuel burns off resulting in heavier exhaust.