2008 R52 cylinder 2 misfire

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by minyme, Feb 14, 2022.

  1. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    Have a 2008 mini cooper r52 with 162733 miles on it. This has been an ongoing problem. The missing got really bad a couple of weeks ago. So I decided to change the plugs, wires and coil pack. Ran fine for about a 20 mile test run right after install. Went to check it out this morning and about 2 minutes after starting it stumbles a bit and the cel comes on. P0302. I did do a compression test a couple of weeks ago and cylinders 1,3, and 4 had 200psi. Cylinder 2.....145psi. I have also check valve springs, none broke or loose. The check gas cap light comes on all the time also. I have an autoenginuity on the way, maybe can do some extensive testing when that gets here. I am needing suggestions on what to look for or check. Sorry for the looooong post.

    Sent from my SM-N960U using Tapatalk
     
  2. MCS02

    MCS02 Moderator
    Staff Member Articles Moderator Supporting Member

    Jul 31, 2009
    10,751
    5,856
    113
    Male
    Ratings:
    +7,323 / 9 / -3
    That’s a big split on cylinder 2. Have you checked fuel pressure? Could be a pump at tome for a new filter. I changed mine at around 100k and it was black.
     
  3. 00Mini

    00Mini Well-Known Member

    Feb 24, 2013
    17,826
    1,231
    113
    Retired
    Ratings:
    +1,902 / 5 / -4
    A leak down test would be very helpful.
     
  4. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    Have not checked that. I assume it's in the tank?

    Sent from my SM-N960U using Tapatalk
     
  5. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    I will try to get that done soon.

    Sent from my SM-N960U using Tapatalk
     
  6. MCS02

    MCS02 Moderator
    Staff Member Articles Moderator Supporting Member

    Jul 31, 2009
    10,751
    5,856
    113
    Male
    Ratings:
    +7,323 / 9 / -3
    Yes it’s in the tank. You can get to it by taking out the bottom part of the back seat. There is an access panel it’s under that panel. I don’t know if that’s it but given the miles if you have never changed the filter it is probably time to do it. The fuel pump could be going bad that is why I think you should check the pressure.
    But the big concern is that you have a P0302 misfire on cylinder 2 and that is the one down on compression. You could do another compression test and on cylinder 2 put a little oil down the cylinder and see pf the compression comes up. If it does you have bad rings, if not you may have a bad valve. Do it first without the oil to confirm your first reading.

    here’s a link to the fuel filter.

    https://www.detroittuned.com/mini-cooper-fuel-filter-g1/
     
  7. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    Here's the results of the wet/dry compression test.
    Dry. Wet
    1. 190. 1. 210
    2. 175. 2. 210
    3. 195. 3. 200
    4. 190. 4. 200



    Sent from my SM-N960U using Tapatalk
     
  8. 00Mini

    00Mini Well-Known Member

    Feb 24, 2013
    17,826
    1,231
    113
    Retired
    Ratings:
    +1,902 / 5 / -4
    This dry test shows cylinders within ten percent of each other which is suppose to show the compression is good. Your original dry test showed #2 cylinder had a real problem but it indicated a much better dry compression result this time. I’m only a shade tree mechanic at best but I have to wonder which test numbers really represent your engine ?
     
  9. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    I think the difference is the engine was cold on the first dry test. If those numbers are within spec, would a bad injector cause a miss. And the miss is not all the time. Just random and at lower rpms. May need to switch the #2 injectors and see if the miss moves with it.

    Sent from my SM-N960U using Tapatalk
     
  10. 00Mini

    00Mini Well-Known Member

    Feb 24, 2013
    17,826
    1,231
    113
    Retired
    Ratings:
    +1,902 / 5 / -4
    Switching injectors is a cheap and relatively easy test.
     
  11. MCS02

    MCS02 Moderator
    Staff Member Articles Moderator Supporting Member

    Jul 31, 2009
    10,751
    5,856
    113
    Male
    Ratings:
    +7,323 / 9 / -3
    Let us know what you find when you change the injectors.
     
  12. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    May be a few days but will update

    Sent from my SM-N960U using Tapatalk
     
  13. 00Mini

    00Mini Well-Known Member

    Feb 24, 2013
    17,826
    1,231
    113
    Retired
    Ratings:
    +1,902 / 5 / -4
    Follow ups are always nice.
     
    • Like Like x 1
    • Agree Agree x 1
    • List
  14. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    Ok. Swapped #2 injector with #1. Went on a 25 mile round trip. Well the misfire code did not come back.......buuut it did throw an p1125, p1126 and p0326. What the heck? I did replace the throttle body last year. So I may be looking at the wiring harness? Haven't went any further. Waiting on my scan tool to arrive.

    Sent from my SM-N960U using Tapatalk
     
  15. 00Mini

    00Mini Well-Known Member

    Feb 24, 2013
    17,826
    1,231
    113
    Retired
    Ratings:
    +1,902 / 5 / -4
    I believe that P1125 and P1126 are for the Throttle body position sensor and P0326 is knock sensor. Could you have disconnected some wiring when working on the engine and not have gotten them reconnected well or jostled the wiring and you were not aware of it or the connections need to be cleaned or sensors are bad and need replaced. So you can check out the wiring connections and if’n that doesn’t help then you’ll be able to give your new scanner a workout. Good luck.
     
  16. MCS02

    MCS02 Moderator
    Staff Member Articles Moderator Supporting Member

    Jul 31, 2009
    10,751
    5,856
    113
    Male
    Ratings:
    +7,323 / 9 / -3
    If you don’t already have this link, this is all the codes.

    https://www.motoringalliance.com/articles/1st-generation-mini-ecu-codes-chart.48/

    You may have already said but what grade gas are you running and is it from a top tear supplier? Long shot but bad gas. Have you cleaned your throttle body lately? You said you just replaced it last year so I doubt it’s dirty, unless you have a K&M type air filter and have over oiled it.

    I’m with @00Mini check all your connections. Also check all your ground wires.
     
  17. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    Yes will go over my connections and check the wiring. We only use premium or non-ethanol. I did put about 5 gallons in it from a local mom and pop store just before the test drive.

    Sent from my SM-N960U using Tapatalk
     
  18. trevhead

    trevhead Active Member

    Apr 15, 2019
    102
    156
    43
    Ratings:
    +168 / 0 / -0
    I went through a long hellish process a year ago to solve a cylinder 2 misfire on my '04 MCS... very very long story but it ended up being worn camshaft lobes. Replaced with a used cam from Allmag and misfire solved.

    Other issues persist, I've been dormant in here for a long time but it's probably time I started a new thread...
     
  19. minyme

    minyme New Member

    May 24, 2015
    19
    12
    3
    Ratings:
    +12 / 0 / -0
    I was just reading your thread. I was thinking i am going to have to end up pulling the head.

    Sent from my SM-N960U using Tapatalk
     
  20. MCS02

    MCS02 Moderator
    Staff Member Articles Moderator Supporting Member

    Jul 31, 2009
    10,751
    5,856
    113
    Male
    Ratings:
    +7,323 / 9 / -3
    Thank you! I remembered someone had this problem but could not remember who!
     

Share This Page