1st Gen R50 Cooper Most liked posts in thread: R50 misfiring on cylinder #1

  1. Eric@Helix

    Eric@Helix New Member
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    May 4, 2009
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    Yep, one would hope that it was put there deliberately, because if trans oil is finding it's way into the #1 plug journal, there's a whole heap of trouble.

    Start with a compression test (inspect the plugs as they come out). It's unlikely that it's your wires, but that's easily tested by swapping the number 1 wire with another one and see if the misfire follows the wire.

    Don't pull the head until you've confirmed that there's a compression issue.
     
  2. jeffster06

    jeffster06 Active Member

    Apr 23, 2010
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    Got the head off this morning, this job was almost too easy. Maybe I just anticipated it being harder, took me 4 hours to get it off, this was with taking breaks and removing the radiator (needs a cooling fan fix) which wouldn't have been neccesary.

    Cylinder one has a burnt exhaust valve. So next up is to get the head fixed/refreshed and reassemble. I still have quite a bit left to fix but I'm happy to get this part partially knocked out
     

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  3. jeffster06

    jeffster06 Active Member

    Apr 23, 2010
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    Figured I'd post an update, heat now works car is running great. Found that the actuator for the temp control was actually stuck, moved it a little by hand now the heat works.
     
  4. RallyMini370

    RallyMini370 Well-Known Member

    Mar 12, 2012
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    I bet it's a burnt out exhaust valve. My R50 had the same issue on #2 anyway as Eric says do a compression check first.
     
  5. jeffster06

    jeffster06 Active Member

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    Yea the handle issue will probably be the easiest to fix lol. Luckily they don't need the car back until mid July so I can take my sweet time, although the longer I look the more I'll find.
     
  6. ColinGreene

    ColinGreene Well-Known Member
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    Yeah, the gain is the exhaust valves wont burn.
    Other than that they are exactly the same.
    might be a good time for a mild cam....:devil:
     
  7. RallyMini370

    RallyMini370 Well-Known Member

    Mar 12, 2012
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    $1200 is ok. this is no a beers only job.....main thing is you cover everything so you don't get some come back later. I say this because I did the V belt job on the Audi with the belt provided by the owner off...............EBAY and the belt broke after 1 month, so he had to take the TT to the dealer as I was in the US. Guess who got the blame??
     
  8. jeffster06

    jeffster06 Active Member

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    I'm fully prepared to offer assistance if there are further issues. I can only assume she will come to me if something goes wrong. Luckily her daughter is out of the US until the middle of July I plan on asking her if I can drive it for a week to shake out any bugs etc
     
  9. jeffster06

    jeffster06 Active Member

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    White or whole wheat, or did you mean paper towels?
     
  10. RallyMini370

    RallyMini370 Well-Known Member

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    I always take the top radiator hose off and pour the fluid in there with the cap and bleed valves open. Never had any issues, heater works great. Maybe the heater matrix is full of sludge? how about flushing the system?
     
  11. cristo

    cristo Well-Known Member

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    I'm wondering if the red ATF was put into the cylinder to do a compression check at the shop (usually you
    check first without and then with some oil or similar added to see if that helps the numbers or not).
     
  12. jeffster06

    jeffster06 Active Member

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    I had that thought as well, but I've always used a few drops of oil. makes me wonder if the shop did a compression check and found cylinder one reading low.
     
  13. jeffster06

    jeffster06 Active Member

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    I have been searching for this issue and came across the burnt valve threads, I really hope its not that.
     
  14. aslondon

    aslondon Member
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    Please keep us posted. Inquiring minds want to know.

    Al
     
  15. ZippyNH

    ZippyNH Well-Known Member

    Jan 25, 2010
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    Hate to say...a burnt valve is preferable to a piston/ring issue....sure the head comes off, but the engine stays in...
    A good compression check, wet and dry by a pro, will give you a good idea what's up...
    Good luck.
    Guess you could move the injectors...use new o-ring if you do too see if it follows the injector, but gut says valves....so many have gone over the years, some due to low octane fuel letting the valves run hot, some from just wear.
     
  16. ZippyNH

    ZippyNH Well-Known Member

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    P.S.
    Misfire at low rpm is typical of lower compression....
    As the rpms increase, there is less time for the air to leak out on the compression stroke...
    So symptoms match...if it is the valves it typically worsens rapidly....
     
  17. ColinGreene

    ColinGreene Well-Known Member
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    Leak down test would be better.
     
  18. RallyMini370

    RallyMini370 Well-Known Member

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    Well if it is a burn valve I have the original head in the garage as I fitted a MC head with better valves. if you need a valve I can send you some. Gratis!
     
  19. jeffster06

    jeffster06 Active Member

    Apr 23, 2010
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    I have learned some more info on the car today, The shop that has been working on it did a compression test and cylinder 1 was half the tolerance it should be (didn't specify the number). Looks like the head will be coming off.

    Before I go pulling the head is there anything else I should check for?

    Also if I pull the head what are some other items I should tackle while in there, new timing chain? etc.... this MINI has approx 117K on it.

    Should mention the shop that has been working on the MINI seems to know what they are doing but my co worker is having sticker shock as the repairs are amounting to almost the purchase price of the car (oil pan gasket and passenger axle are bad as well). I just happen to be a nice guy and won't charge her what they were going to.
     
  20. RallyMini370

    RallyMini370 Well-Known Member

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    This is how I found out it was a burnt out valve: I took the valve cover off to see when both valves were closed on the suspect cylinder. I then connected an air line to the compression tester line. I blew air into the cylinder and then put my hand over the tail pipe. I could feel air coming out which confirmed the burnt out valve.