CLK 320 W208 performance / codes

Discussion in 'Engine' started by steadyeddie, Sep 4, 2017.

  1. steadyeddie

    steadyeddie Active Member

    Messages:
    96
    Joined:
    Mar 7, 2011
    Car:
    Mercedes CLK 320 W208
    Hi,

    So a few months back now I was chasing a gremlin that was causing my car to lose power and then judder heavily at idle.

    I replaced the MAF, TPS, leads, coils, fuel filter etc to no avail.

    I visited an independent Merc Specialist twice who charged me an hour labour each time. First time was just to read codes and second time told me I most likely had a blocked catalytic converter and wanted to charge £1,200 for a new exhaust.

    Subsequently went elsewhere to have the cats removed. Car still had the problem and now sounds like crap. :mad:

    Anyway...a couple of weekends back I was checking all vacuum hoses in the engine for signs of a leak. I tightened every screw / jubilee clip I could find.

    SUCCESS! The car now no longer cuts power under acceleration or judders.

    I have purchased an ODB reader and adapter and was able to read the fault codes, however I have not been able to clear them.

    The car also still feels quite sluggish and I'm wondering if clearing the codes will help?

    If it's not the codes I can't possibly think what could be the cause.

    Many thanks in advanced,

    Ed
     
  2. OP
    OP
    steadyeddie

    steadyeddie Active Member

    Messages:
    96
    Joined:
    Mar 7, 2011
    Car:
    Mercedes CLK 320 W208
    I should add that in two weeks time I'm driving down to Lake Como in Italy and would love the car to be in the best shape possible.
     
  3. markmifsud

    markmifsud Hardcore MB Enthusiast

    Messages:
    2,125
    Joined:
    Nov 17, 2008
    Location:
    Bromley, London
    Car:
    CLK320 CAB (A208) 02
    I guess others might be able to help if you posted the codes? Did you get a copy of the original diagnostics?

    I would assume that either your ODB reader isnt communicating with the car to clear the codes, or they are still current faults so will still show.
     
  4. OP
    OP
    steadyeddie

    steadyeddie Active Member

    Messages:
    96
    Joined:
    Mar 7, 2011
    Car:
    Mercedes CLK 320 W208
    The original codes were:

    P0150 O2 Sensor Upstream
    P0306 Misfire Cylinder 6

    Both O2 sensors also replaced.

    It was on the second visit I was told about the possible blocked cat.
     
    Last edited: Sep 4, 2017
  5. PobodY

    PobodY Hardcore MB Enthusiast

    Messages:
    2,308
    Joined:
    Aug 23, 2016
    Location:
    Stoke-on-Trent
    Car:
    CLK350 Sport, Nissan GTiR
    A misfire on one cylinder would certainly make the running uneven. - I assume it's definitely sparking on cylinder 6?

    If you take the plug(s) out of that cylinder, what do they look like? - Hopefully like they should and not oily or sooty.

    Can you get another lambda sensor (even a used one) to rule that out?
     
  6. DSM10000

    DSM10000 MB Club Veteran

    Messages:
    5,080
    Joined:
    Jul 12, 2011
    Location:
    Near Salisbury
    Car:
    E32O CDi Sport, MX5 1.8 Sport, RR 4.2 SC
    Try changing the coil pack to one from another cylinder and see if the fault moves.
     
  7. crisc204

    crisc204 Hardcore MB Enthusiast

    Messages:
    138
    Joined:
    May 8, 2007
    Location:
    Londinium
    Car:
    w208 Coupe,
    The Cat is outrageously dear from Mercedes even worse if you have a pre facelft w208 iirc so £1200 is not a totally outhere figure...

    Follow advice from others as above
    If they won't clear they are current/active faults

    Its normally a failed or failing coilpack or worn/fouled plugs that cause this kind of thing.

    When did it last have a set of Spark plugs?
     

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