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Loss of throttle power at high rpm's

Discussion in 'E39 M5 (2000-2003)' started by Remoun, Oct 14, 2008.

    Remoun guest

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    Help!!! I don't know what's wrong or how to fix it.

    A week ago my E39 started to act up. At high RPMs (5000 to 6000) I get a sudden loss of throttle. It doesn't matter if I am in sport mode or not. I then have to wait until the RPM's drop below 3000 RPMs or shift into 5th or 6th gear to force the RPM's to drop below 3000. Once the RPMs are below 3000 I get my throttle back however it doesn't deliver as much power as normal. To reset the problem I have to turn the car off and back on.

    Any ideas? Is it the computer? Would a BMW tech be able to plug it into his computer and find out the problem? Please help!

    stosman guest

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    I have a 2000 M5 which just developed a similar issue. The service engine light came on immediately though. I cruised home, and when I restarted the car all was well. i took it to my Non dealer BMW Tech to run a diagnostic on it and multiple codes revealed Cam sensor and possibly Vanos issues. I am awaiting the complete diagnosis. So much for my 401K if it's the Vanos!!
    Regards,
    Christos

    Remoun guest

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    I replaced the cam shaft position sensor about 3000 miles ago. This weekend I replaced all spark plugs along with all new coil packs. I used the high performance coil packs from Bavarian. Spark plugs were purchased from BMW. Problem still exists. I'm getting misfire codes from the computer but can’t figure out what else it can be.

    BMWguy206 guest

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    Yes but which camshaft position sensor? You have a total of 4. 2 intake and 2 exhaust.

    What other faults are you getting? Have you replaced the fuel filter recently?

    Remoun guest

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    I replaced the exhaust-2 sensor due to an error code I received. The codes I’m getting now are various misfires. No, I have never changed the fuel filter. Do you think that could be the problem? I have 62K on the vehicle.

    Remoun guest

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    I just replaced the fuel filter. problem still exists.

    Mbrother guest

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    Do you have a Peake tool to read the codes? If you don't you might need to take it to a BMW Tech (hopefully not a dealer) to have them read the codes and diagnose exactly what is wrong. www.bimrs.org has reputable BMW Techs if you currently don't have one.

    You can also post your question on the m5board.com, VERY knowledgable folks there!
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    mooseheadm5

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    Still have any codes? Bank 2 is driver's side, BTW.

    Remoun guest

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    I'm going to my BMW tech this weekend. Stand by.

    Remoun guest

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    Here are the two codes I got:

    129 - Internal Index 73
    178 Catalytic Converter

    Any Ideas?

    coop269 guest

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    The only way to properly diagnose a concern like this is to physically have the car in front of me with BMW diagnosis equipment. I can say that as a master tech I have seen issues like this caused by dirty mass air flow sensors (easily cleaned with a $3 can of MAF cleaner). If you're getting codes for the catalytic converter the DME may be putting the system into failsafe to prevent damage to the cat. I would recommend taking the MAF sensors and cleaning them off before spending a lot of money on other things.

    Remoun guest

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    ok...cleaned the sensors. Problem is still there. Can they just be bad? I have 68k on it.

    Filters look ok. Can the car not be getting enough air?

    Can it be an O2 sensor?
    Crank Position sensors?

    Maybe its just time to drop the big bucks and have it looked at.
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    mooseheadm5

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    It is likely not the O2 sensors. It may or may not be a crank sensor. You need have someone scan it.

    coop269 guest

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    Without the BMW equipment this can be tricky. I would suggest checking the fuel pressure (easily done thanks to the schrader valve on the fuel filter assembly.) Try to get a nice long hose on the gauge so you can tape it to the windshield and drive the car. Try to get it to go into failsafe again and when it does keep an eye on the fuel pressure. If you see a drop in pressure you have a bad fuel pump. You should be running at 5 bar of pressure under full load. I have seen a few of these pumps go bad, but not too many.

    Remoun guest

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    It turned out to be the MAFs. I tried cleaning them but they only lasted a few months longer. When replaced the problem is fixed.

    Thanks for the posts

    Mbrother guest

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    Congrats!!!

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