2nd Gen R56 Cooper S SPUTTERING on cold start

Discussion in '2nd Generation: 2007+ R55 through R61' started by Cuffington, Sep 23, 2013.

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  1. Cuffington

    Cuffington New Member

    Sep 23, 2013
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    #1 Cuffington, Sep 23, 2013
    I own a MCS 2008 with 37,000 miles. The last 2 weeks it doesn't start with it's usual gusto... it sputters (doesn't knock) and sometimes starts after about 20 seconds, but sometimes just quits... I took it in, and the computer showed it was "misfiring on 2 and 4"... my mechanic ?'s if it's carbon buildup (no access to a Mini dealer) and he is not able to do the "Walnut scrub"... he told me to quit puttering around, and get the engine warm on every outing... I always drive around 80-90mph, for at least 20 minutes/twice daily... "Puttering" is rare for me. So now, to prevent the engine lite from going on, I start it, and if it doesn't start right up, I shut it down, and try again until it fires up (2 or 3 tries)...then it fires right up and I'm racing again... Any other ideas??? Is it Carbon??? Do any additives help?
     
  2. CHKMINI

    CHKMINI Club Coordinator
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    #2 CHKMINI, Sep 23, 2013
    Sounds like carbon to me. Additives won't help.
     
  3. nxtMINI

    nxtMINI Active Member

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    #3 nxtMINI, Sep 24, 2013
    Seafoam engine treatment will do the trick. I do it every other oil change to prevent carbon build up.
     
  4. Nathan

    Nathan Founder

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    #4 Nathan, Sep 24, 2013
    Welcome, thanks for joining Motoring Alliance, the FUN and Friendly MINI Community.

    Have you pulled the spark plugs and checked them?

    I'd also look at the plug wires, make sure they are seated well.
     
  5. Crashton

    Crashton Club Coordinator

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    #5 Crashton, Sep 24, 2013
    I'd say carbon too. On a cold start the carbon literally soaks the fuel into it making the mixture too lean. Happens on any engine with a lot of carbon in it.

    As far as seafoam goes no one has shown any proof that it works. Don't know if it would hurt or help. The fix that does work is walnut shell blasting.

    Good luck & welcome to M/A....
     
  6. Twistee

    Twistee New Member

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    #6 Twistee, Oct 10, 2013
    Last edited: Oct 14, 2013
    My 07 MCS was doing the exact same thing. Mine got to the point that it took several tries to get it started.

    In my case it was a fuel pump- A known issue and replaced under warranty. There is a service bulletin explaining the issue and warranty period extension. A google search for 'r56 high pressure fuel pump warranty' will yield a lot of folks with the same issue- discussion at motoringfile- and a thread on NAM

    Mine also threw the misfire code on my obd reader- the misfire was a symptom, not the cause.

    A phone call to a MINI dealer may explain specifically which fuel pump it is, my dealer in San Antonio was familiar with the issue and Robert's your father's brother.
     

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