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Thread: 750iL misfire with fuel cut off

  1. #1
    Join Date
    Jan 2012
    Location
    Redding, CA
    Posts
    18
    My Cars
    1999 BMW 750iL

    750iL misfire with fuel cut off

    I'm getting super frustrated with my 99 750

    About 8 months and 6,000 miles ago (I don't drive it much) I noticed a misfire when I'd stop at a light. No check engine light, and to be honest, I didn't think it was a misfire at first because it was so subtle. (As stupid as it may sound) I thought it was my self leveling suspension twitching or something along those lines because I had just picked up a set of wheels and had a lot of weight in the trunk and back seat when I noticed this started. I just figured I had messed something up and would look into it.

    Then after another 500 miles or so, I finally realized it was a misfire (still no SES light). I figured I needed to change the spark plugs and coils on the account of being so close to 100K. So, after another couple thousand miles the misfiring went from once every 100 miles to constants misfires while idleing. I finally got around to changing the coils and spark plugs. I went to my local dealer to buy the plugs and coils. I was a little intimidated by changing the plugs because of the location but it was actually very easy.

    So I figured that would fix my problem, but now, 500 miles after changing the spark plugs and coils (99,700) the car misfires all the time and if I give it to much throttle it will throw the SES light and shutter as if its cutting power. All I have is an OBD reader and I check the codes. Its always cylinder 4 and 10 and the codes say misfire with fuel cut off.

    Another detail is that when it is hot, it is 10 times worse. Today it was 102 where I'm currently at and it was everything I could do to get her to 45 mph. If I pushed the throttle past 10% it would stutter and misfire uncontrollably (I monitor the OBD readings on my iPhone). Now that it's evening and has cooled down it is so much better, but far from normal.

    My questions is, what could it be?

    Plugged cat(s)?
    Faulty TPS?
    Distributors?
    Vacuum leak?
    Faulty CPS?


    I'm not sure if anyone else has had this same problem but if you have, please let me know what you did to fix it.

    Here are the codes it is throwing-

    P1361
    P1363
    P1349
    P1341
    P1585

    Any help is appreciated!

    Dalton

  2. #2
    Join Date
    Jun 2007
    Location
    Irvington, NY
    Posts
    1,603
    My Cars
    540iT, 750iL, Cooper S
    Have you looked at cam position sensors?
    99 540iT, Jet Black on Black. Dinan mods ( CAI, MAF, TB, Brace, Stage 4 engine and tranny software ). 00 750iL, Jet Black on Black. MPars, Sport Steering wheel, alpina replica lip. 05 Mini S, Dinan CAI, Strut brace, UUC exhaust.

  3. #3
    Join Date
    Oct 2009
    Location
    Multiple States
    Posts
    3,056
    My Cars
    01 750iL
    start checking for vacuum leaks. The lines running under the noise cover to the bottom of the throttle bodies (especially the drivers side) I have had issues with.

    also, if it has been replaced it is likely the wrong size. I think it was a 3.5 mm hose and it should say that on the hose. If it has american measurements it's the wrong hose.

    the parts store hoses were just a bit too loose or too tight.

    richard
    WTB: Dinan Spring set, for the 750iL

    You work hard, discover that success is not a destination but rather a road you travel upon- mostly up hill. Then, after a while, people going down the other road look up at you, and they call you "lucky."

  4. #4
    Join Date
    Jan 2012
    Location
    Redding, CA
    Posts
    18
    My Cars
    1999 BMW 750iL
    Quote Originally Posted by noodlesandsam View Post
    Have you looked at cam position sensors?
    I have not checked them out yet. How many are on the 99 V12?

    Quote Originally Posted by darkstarmedia View Post
    start checking for vacuum leaks. The lines running under the noise cover to the bottom of the throttle bodies (especially the drivers side) I have had issues with.

    also, if it has been replaced it is likely the wrong size. I think it was a 3.5 mm hose and it should say that on the hose. If it has american measurements it's the wrong hose.

    the parts store hoses were just a bit too loose or too tight.

    richard
    Thanks, I will check the hoses and let you know what I come up with.
    Last edited by GranCabrio; 10-02-2012 at 08:38 PM. Reason: Automerged Doublepost

  5. #5
    Join Date
    Jun 2007
    Location
    Irvington, NY
    Posts
    1,603
    My Cars
    540iT, 750iL, Cooper S
    Just one. E38.org. Read it, memorize it, become one with it

    RY
    99 540iT, Jet Black on Black. Dinan mods ( CAI, MAF, TB, Brace, Stage 4 engine and tranny software ). 00 750iL, Jet Black on Black. MPars, Sport Steering wheel, alpina replica lip. 05 Mini S, Dinan CAI, Strut brace, UUC exhaust.

  6. #6
    Join Date
    Jan 2012
    Location
    Redding, CA
    Posts
    18
    My Cars
    1999 BMW 750iL
    I finally replaced Camshaft Poistion Sensor and Crankshaft Position Sensor... No luck

    Now that it's cooling down, I have noticed more details. When it's cold (below 60 degrees) the car runs like a champ. No misfires at all. I have full power under 100% throttle. Around 85 degrees, the car does okay but far from normal. Misfires and power loss. When it gets to 90-100 degrees the car hardly runs. Constant misfires on the same 3 cylinders, no power and hardly drivable.

    Another thing is that there is a popping noise that you can hear when idling. I can't tell where it's coming from but sounds like its near the front of the engine. It's not a ticking, but more of an electrical pop or click.

    My questions is, what could be so affected by ambient Tempature to cause this problem?

  7. #7
    Join Date
    Apr 2007
    Location
    Kansas City, MO
    Posts
    6,718
    My Cars
    2x01 750, 01 740
    MAFs are probably the most affected by ambient temperature. They are also known to cause misfire stopping at a light.

    The clicking when idling is probably the charcoal filter valves - perfectly normal.

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