R56 '09 MCS Possible Carbon Build-up Issue?

[BlueBomberRC83]

Hi everyone. I have a 2009 R56 Cooper S with approximately 100,000 km (62,000 miles). Lately, I started to notice that the engine is idling kind of rough, to the point that twice I got the warning on the CBS display indicating half-power (or power-loss). I've changed my spark plugs recently, but the engine still idles rough.

I started reading through these forums (as well as others) and it sounds like the problem is carbon build-up around the intake valves, according to the symptoms. I'm not the most tech-savvy person, but from what I've read, there are a few solutions/aids to the problem: Seafoaming, PCV delete, OCC, walnut shell blasting. So now, I have a few further questions regarding this issue and I appreciate any suggestions/comments regarding this issue:

1. Did I misdiagnose the issue? It's not the high-pressure fuel pump? It's nothing to do with oil level and/or the timing chain (which I had replaced under warranty in 2012)?

2. Am I correct in stating that if I perform a PCV delete, I can no longer do the Seafoam method? Seafoam is supposed to go into the PCV hose that's recommended to be deleted, correct?

3. Is it okay to do Seafoam treatment in -10 Celsius weather? If so, should I warm the car up first before doing the treatment, or can I just start the engine, cold?

I'm leaning towards doing a walnut shell blasting from the dealership, which apparently comes with a software update to somehow slow the carbon build-up. Dealership wants to charge approximately $600 for blasting and software. I would like to go this route because I've never done any preventative work with respect to the carbon issue, and I read Seafoaming wouldn't get rid of the stuff that's caked on. Afterwards, I will probably do Seafoam treatments before every oil change (12,000 km, 7500 miles) to get rid of the newly accumulated carbon. Hopefully I won't have to do another carbon blasting in the next 100,000 km.

Anyone see a problem with my plan? Again, suggestions/comments are greatly appreciated. Thanks.

[george_talbot]

Don't block off the second PCV line, in my experience it increases oil consumption and lag.

If its idling badly/spluttering/misfiring then it could be the high pressure fuel pump. This is my car with a faulty pump:

Mini Cooper S R56 Engine/Cold Start Issues -...

[BlueBomberRC83]

Quote: Originally Posted by george_talbot (original)

Don't block off the second PCV line, in my experience it increases oil consumption and lag.

If its idling badly/spluttering/misfiring then it could be the high pressure fuel pump. This is my car with a faulty pump:

Thanks very much for your reply! I'm not sure if my car sounds the same when the engine power is halved as I've always remained in the vehicle; it's below freezing outside. However, I also notice that restarting the engine tends to clear the issue.

I understand that my vehicle *may* have the 10 year/120,000 mile extended warranty on the HPFP (but I live in Canada, so I'll likely need to fight for it). I'll see about getting it replaced.

Duly noted, regarding the PCV hose. I think I will pass on the PCV delete and OCC. For the carbon issue, I'll likely do the carbon blasting and possibly do Sea Foam treatment.

Thanks again!