1st Gen R53 Cooper S No idle, misfire

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by limitedxj, Feb 12, 2013.

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  1. limitedxj

    limitedxj New Member

    May 19, 2011
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    2005 mini cooper s, 15% and +2 balancer.
    Mini cooper s drove in a rain storm from Atlanta to knoxville with no problems, in knoxville hit a large bump on the interstate immediately felt a vibration, all lights came on including the door open light. pulled over let off gas the mini died.
    To start the car you have to give it gas and it will only run when throttle is depressed, let off it dies. codes were for a #4 misfire and O2 sensor.
    Replaced the coil pack with extra, #4 and #3 were heavily corroded, replaced the wires, no help. Pulled the #4 spark plug, is wet with what smells like gas, replaced with stock plug, no change in running. check engine light flashes briefly, the traction control light comes on then the engine light stays on.
    at a loss on what to look at next, the inability to even idle roughly on its own has me thinking its fuel related or vacuum, internet searches have not found anything that fits my issues fully.
    any help will be appreciated.
     
  2. Nathan

    Nathan Founder

    Mar 30, 2009
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    This might sound odd but check the relays under the hood to make sure they are plugged in all the way. Large bumps can and have in the past popped them out a little to the point where there were odd issues when running and even the car not running at all.
     
  3. limitedxj

    limitedxj New Member

    May 19, 2011
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    upon further inspection today, the metal piece in the belt tensioner has broken off and the pully now rest against the balancer, don't know if this is the problem or a effect of the misfire which is violent. anyone with a similar story let me know.
     
  4. limitedxj

    limitedxj New Member

    May 19, 2011
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    removed the belt and tensioner, the tensioner is now in 2 pieces. tried to start the car with no belt just to see if it would idle, no luck, acts the same.
     
  5. limitedxj

    limitedxj New Member

    May 19, 2011
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    No compression in #4, all other cylinders at 125. Here's hoping its just a spring and not a bent valve or cam issue.
     
  6. yellowbritishrocket

    yellowbritishrocket Well-Known Member

    May 16, 2009
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    sounds like when the tensioner smacked the balancer it probably locked up the engine long enough to foul up the valvetrain...i would get that valve cover off quick and check you could very have bent something or dropped a valve...

    i take it you were using an alta balancer? the problem with those lightweight crank pullies is yes they are lighter...but in regards to the fact you have a tensioner under alot of stress and tension above it...to me its almost like its a guillotine that is spring loaded...one good whack and it comes down hard on that balancer
     

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