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What can i do to clean carbon build up? - BMW Cars & Trucks

Posted by tammiegray on

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  • tammiegray
    tammiegray Feb 16, 2012

    Thank you for responding. Do you know the name of the product? I also had a coolant low light to come on yesterday, filled the resouvoir and light went out. I took to dealer friend and he said aux water pump is goin bad, could this have something to do with failed SAI with Inspection testing?

  • Marvin
    Marvin Feb 16, 2012

    I don't know the name BMW sells it under just that it is designed to decarbon the upper cylinder of the engine. Ford dealer parts also has a great product as well under the Motorcraft name.

  • Marvin
    Marvin Feb 16, 2012

    Yes it could. I would also suggest you clean the throttle valve and idle control motor, do the following to clean them up. It will lower the low speed test levels of HC gas.
    Buy a can of throttle valve cleaner (it is made by CRC) from the local auto parts store, NEVER USE CARB CLEANING SPRAY, IT DESTROYS THE ANTI-STICK TEFLON COATING, spray it into the air intake through the throttle body of the engine until you have used about half the can, you will need to hold the idle up while you do this, it will try to stall, after this shut the engine down and disconnect the Negative (-) battery cable for 5 minutes. The intake is now clean, if you continue to have the idle speed control problems you may need to seek the help of a professional.

  • Marvin
    Marvin Feb 16, 2012

    I assume that SAI is what we call a smog inspection here in California

  • tammiegray
    tammiegray Feb 17, 2012

    SAI is secondary air injection

  • tammiegray
    tammiegray Feb 17, 2012

    ok so I did a full fuel system cleaning with throttle clean before the bank 2 air valve and hose was replaced...reset the code and drove it about a week and a half and day before yestesday the same code came back po492... i took apart the air flow hose and the li lsmall port on it seemed to be clogged..clean it and reconnected the hose..very slight pulse when idle... thoughts?



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The BMW dealer sells a chemical that helps get rid of carbon, you let it (the engine) **** the can dry through one of the engine's smaller vacuum lines, hold the speed up as the engine will try to stall, then shut off the engine and let it sit for an hour longer if possible, then blow it out on the freeway with some spirited driving

Posted on Feb 16, 2012

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We had this problem in a 135 and the best way to get rid of it is to clean out the intake with high pressure crushed walnut shells. Once you have it clean, have your mechanic install a catch can and that will collect all that soot and keep it out of your intake manifold.

Posted on May 02, 2019


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