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  1. #1
    Join Date
    Feb 2018
    Location
    Flourtown, PA
    Posts
    5
    My Cars
    2004 BMW X5 3.0

    Low Compression and Misfire

    Hi, I have researched my problem on this forum and watched tons of videos. I am ready to ask for help and opinions.
    Thank you very much in advance...


    The car is a 2004 X5 3.0 with 230k miles.
    I have not owned it long (a few weeks and less than 100 miles) and I got it cheap - and now know why.
    It drove fine for a few days (50 miles or so - various speeds)
    Noticed Oil was low and a little cruddy looking - added 2 Qts of new M1 Syn 0/30 to get it up to full. Planned on Oil Change in a few days.


    When driving the car - highway speed, the check engine light went on and the car started running rough.
    Misfire on Cyl 3
    Changed plugs (none looked too bad, no major oil, no major ash, etc. Changed to NGK 4-prong plugs.
    Changed coils - noticed that Cyl 4 coil was different but none looked bad, no oil or cracked boots, etc. Changed them all anyway.
    After coils and plugs, still running very rough and misfire on Cyl 3.
    Swapped a couple of coils and plugs to rule out bad coil/plug - no change
    Installed new Fuel injector on Cyl 3 - No Change
    Sprayed some ether around running engine to see if there was a vacuum leak - no engine speed up and don't see any cracked or bad hoses - prob need to look further.
    Compression Test on Cyl 3 - 30!
    Compression on 2 and 4 - Greater than 150 - did not test the others.


    Put scope down Cyl 3 - did not see any holes or anything on top of piston. Walls of Cyl looked good - no scars.
    I did not get to look at the valves because the mirror on the scope sucks and I did not want to fish it out of the cyl if it broke. Going to borrow a better scope to look at valves.


    I put Rislone in Oil and ran and drove the car - did not notice much difference
    I bought some of the blue (flat bottle) BMW branded injector cleaner and put a couple ozs in Cyl through plug hole and let it sit overnight.


    Just started it and ran in driveway. Lots of smoke from the treatment.
    After it cleaned out and stopped smoking, new compression test. Got 60.
    I just dumped some more of the blue cleaner in and will let it sit for the day and try again to see if it gets better.


    So not sure what to do next.
    Scope Valves?
    Remove Valve Cover and inspect springs and try to look at valves from top?
    Remove Head and get better look at valves from bottom, cyl and pistons?
    I can buy a leak-down tester and try that too?


    Other notes -
    The engine does not make any bad noises, you can hear the misfire but no mechanical noises, clanking, valve noise, etc.
    You can hear the timing and or vanos chain but not loud.


    Open to thoughts, suggestions and next steps.
    Again, thanks!

  2. #2
    Join Date
    Dec 2011
    Location
    Lancaster CA
    Posts
    5,051
    My Cars
    e34,e38,e39,e46,e70,e90
    You checked for vacuum leaks, assume all ok.
    Check compression on all cylinders just to confirm all are ok.
    Good job replacing plugs and coils.

    Three things to check. 1. Air, 2. Fuel, 3. Fire

    1. Air - Valve cover gasket OK? If any oil leaks it could allow vacuum leak in head and bad running multiple misfires. Also make sure the oil cap is secure and the rubber seal is there and sealing. Check secondary air pump (I think your engine has one) along with all the hoses from the head to the throttle body. The ICV could also be a culprit.
    2. Fuel - Check for proper fuel pressure, but usually a bad pump will cause a no start situation
    3. Fire - you changed the plugs, so good there.

    If all that checks good, you may have failing cats causing too much back pressure and causing the misfires. At 230k miles, they do go bad. An easy way to check is to pull the pre cat O2 sensor and see if the car runs smoother.

    Good luck, hopefully its something simple and cheap.
    Last edited by kouks; 02-08-2018 at 05:43 PM.

    02 e39 540i Sport (Son), 01 DINAN 7 (Me), 12 e70 X5 x35i (Mrs), 95 e34 525i (Daughter 2), 01 e46 325Ci vert (Daughter 1)

  3. #3
    Join Date
    Feb 2018
    Location
    Flourtown, PA
    Posts
    5
    My Cars
    2004 BMW X5 3.0

    Next Steps - Thanks for the help

    Thanks a lot for the assistance.

    This morning, I did another compression test of all cylinders. Here are the results:

    1 - 210
    2 - 195
    3 - 0
    4 - 150
    5 - 160
    6 - 175

    I have been able to get Cyl 3 to get up to 50 but cold, right now it is 0.

    I took off the valve cover.
    Gasket seemed OK - a little brittle but not terrible. I would not think it would be bad enough for 0 Compression on C-3.
    Everything looked pretty good from the top.
    No major sludge
    VANOS and chains looked OK.
    There was some yellow gunk on the back side of the top of the valve cover - over Cyl 5-6.
    Cam lobes looked good.
    Top of valves looked good.

    At this point, I am thinking Head Gasket or Rings on Cyl 3
    I am not sure how rings could fail and not have any bad noise but I am not the expert.

    Any thoughts or suggestions will be most appreciated.

    Thanks










    Quote Originally Posted by kouks View Post
    You checked for vacuum leaks, assume all ok.
    Check compression on all cylinders just to confirm all are ok.
    Good job replacing plugs and coils.

    Three things to check. 1. Air, 2. Fuel, 3. Fire

    1. Air - Valve cover gasket OK? If any oil leaks it could allow vacuum leak in head and bad running multiple misfires. Also make sure the oil cap is secure and the rubber seal is there and sealing. Check secondary air pump (I think your engine has one) along with all the hoses from the head to the throttle body. The ICV could also be a culprit.
    2. Fuel - Check for proper fuel pressure, but usually a bad pump will cause a no start situation
    3. Fire - you changed the plugs, so good there.

    If all that checks good, you may have failing cats causing too much back pressure and causing the misfires. At 230k miles, they do go bad. An easy way to check is to pull the pre cat O2 sensor and see if the car runs smoother.

    Good luck, hopefully its something simple and cheap.

  4. #4
    Join Date
    Jan 2016
    Location
    Montreal/Cape Coral
    Posts
    207
    My Cars
    2012 X6 35i
    You keep coming up with low/no compression on #3 on an engine with 230k miles. Face it bro, you'll have to tear into the engine, heads at the very least...
    2007 FJ Cruiser (best vehicle to date)
    2012 X6 35i Sport
    2013 ML350 BT
    2019 4Runner

  5. #5
    Join Date
    Dec 2011
    Location
    Lancaster CA
    Posts
    5,051
    My Cars
    e34,e38,e39,e46,e70,e90
    0 compression usually is not the head gasket, unless something else really bad is going on. Your possibilities are broken valve, cracked head (big crack) or cracked block (again, major failure), and maybe the rings, but those would go slowly, not dramatically.

    1. A broken valve is usually caused by excessive heat, which can be caused by failing/blocked cats, so you may have bigger problems too.
    2. Cracked head is due to overheat, so is a failed head gasket normally, oil and coolant may be mixed
    3. Cracked block, usually caused by extreme pressure and overheat, and oil and coolant mixed

    Unless you really love this particular X5 at 230k miles, you need to make a decision to either replace the engine completely, tear it apart and fix or rebuild as needed, or admit the car is dead and was a bad purchase and junk it (or part it out). Its all about money.

    If you want to get a good idea of what is broke without tearing into the engine first, look at youtube videos and perform a leak down check. That way you can determine if its valve, cylinder or rings.

    02 e39 540i Sport (Son), 01 DINAN 7 (Me), 12 e70 X5 x35i (Mrs), 95 e34 525i (Daughter 2), 01 e46 325Ci vert (Daughter 1)

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