E86 Emissions Issue

[spike71]

Hi - new to the group with my silver 2008 E86 with 68k miles. U fortunately, car failed recent MOT with high CO at Fast Idle 0.28 instead of 0.2 and 0.43 instead of 0.2 at Second Fast Idle. Plugged it in at BMW dealer and no fault codes, car drives well. Took it for a ‘Terraclean’ hoping this would sort any ‘gunk’ build-up as I’d not used it much in the last year, but still failed!! Grateful for any thoughts as BMW mechanics are baffled…..as am I

 

[MikeyH]

Sorry I can’t help but welcome to the forum. someone will be along soon who will know.

 

[Mr Tidy]

Hi and welcome to the forum - Coupe is the right choice too.

Sorry I can't help with your problem either. I've had 4 cars with the N52 engine and never had that issue. My only thought is was the engine properly up to temperature when it was tested?

 

[spike71]

Yes. Engine warm and toasty before the MOT. Great car, now sat on my drive unfortunately…..

 

[Joez4]

Check fuel trims and readiness monitors ,could be an issue with o2 sensors or cats would expect codes tho,

Could try a bottle of catclean in fuel tank and give the car a really good blast before mot test

 

[raymond.harper]

It may be of value to look at other BMW sites with N52 engined cars . https://www.e90post.com/forums/showthread.php?t=1760656

 

[spike71]

Thanks for replies. Used cataclean prior to MOT but didn’t help. Could be sensors on way out, but not bad enough for a fault.

 

[Mr Tidy]

I did get an amber EML in my 2nd E86 that was for the post-Cat 02 sensors. My Indy put a does of Cataclean in it and told me to fill it with Shell V-Power then take it for a long drive.

That worked for a few months but then the amber EML reappeared, so it got another dose of Cataclean, etc. and that seemed to cure it.

But it passed an MOT between those two episodes.

 

[Mike6]

Has oil been changed and oil filter. Also check air filter, they often get overlooked and can clog up restricting airflow.