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Decoking? Questions

9K views 8 replies 6 participants last post by  Wynnston 
#1 ·
Hi

New to the mini but wondering about the Decoking issue that seems to plague these engines

I have the 2010 clubman s (184bhp version)

I have a bit of a rough idle, uneven power distribution when the engine is cold. This appears to disappear when the engine is warm. Probably within the first 5 minutes of driving. It seems quick enough on normal driving and in sport mode. No signs of hesitation there.

The car has done 32000 miles.

Question is, how do you know it is coked up??

Should I be concerned at the mileage we are talking about

Who is best in the northwest to inspect and deal with this


I ask all this because I'm looking into tuning, Chip, map and exhaust work and obviously the engine needs to be sorted/or deemed fit before I go about making upgrades.

Many thanks again

Mike
 
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#2 ·
Hi ya

Normally when you have a carbon problem it will show up when the car is hot and under load, you would get a misfire and hesitation.

It could be a lot of things causing your issue, when was it last serviced.
Have you run any bg44k fuel system cleaner throw it.

My advice get an air/oil separator fitted this will help prevent carbon build up

Hope this helps
 
#3 ·
Really common on the pre-LCI models. Really heavily discussed. Can be so subtle you don't even know.

For the record a catch can (from new) will reduce it, but won't stop it, or fix it once you have it.

Subaru have used a can of intake cleaner every service for years. Looking like this is good practice on every direct injection engine. Fuel additives don't work because the fuel goes directly into the engine and not sprayed onto the valves (where the buildup is).

We had a club event with close to 20 cars. Only 1 person could notice anything was wrong. All (on the dyno) were down close to 20hp and blowing black smoke under load. Only proper fix is to get an intake blasting professionally done (~$400).

By the time you feel the hesitation you have a really big problem ;)
 
#6 ·
anyone that buys a DI engine is a test bed! earlier cars were bad, as its quite an xtra $$$$ for a few mpg. manufacturers were "forced" to use it to meet ever tighter government regs, we get the "banana" in return. i feel that very robust low noack oils like Amsoil real synthetic group IV +V oils can help. not a fan of the x-20 oils as a 10-30 will holdup better all around
 
#7 ·
My understanding is that once you've had a good carbon clean - the proper walnut one, then you install a catch can and your problems shouldn't arise again.

Also, changing your oil every 5000 miles or less will help a lot in general.

Downside is that the carbon clean is $400-500 and a catch can is $200~ + installation if you're not a DIY'er.
 
#8 ·
Yep, that seems the case. We have around a half dozen club members with the can.

What we can't explain is one member with one of the first R56 JCWs. The blast did nothing. He doesn't have the catch can. Zero build up on his valves :)
 
#9 ·
Strange. I really don't know if mine are coked up or not, but the car has random super knock issues (throws codes too) which I thought I had cured with a MAF clean, but no joy :(

It also comes up with the unmetered code, so I'm just eliminating the possibilities one at a time. Decoke next :)
 
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