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mhd linear throttle fail

Discussion in 'Troubleshooting' started by squeedle, Aug 27, 2017.

  1. squeedle

    squeedle Lurker

    Messages:
    19
    Location:
    SF Bay Area
    Ride:
    2009 135i AT MSport Coupe
    I've been running an MHD OTS S1 tune for a couple weeks now. This morning I decided to try the "linear throttle" option. So I loaded the same S1 91 octane map but checked the "linear throttle" option. Turned off ignition, then back on. Started it, and car did a bizarre idle where it would kind of rev over and over again once every second or so in a cycle and wasn't responding to pedal input. I unchecked "linear throttle" and reflashed it and it was fine again. Is the "linear throttle" option not ready for prime time? Or am I missing something?
     
  2. kisarci

    kisarci Lurker

    Messages:
    11
    Ride:
    '07 e92 335i
    It sounds like you have to reset adaptations. The exact same thing happened to me
     
  3. squeedle

    squeedle Lurker

    Messages:
    19
    Location:
    SF Bay Area
    Ride:
    2009 135i AT MSport Coupe
    So I should flash the linear throttle map, then reset every adaptation? Then start car?
     
  4. V8bait

    V8bait Sergeant

    Messages:
    297
    Location:
    Texas
    Throttle map shouldn't need an adaptation but maybe worth a shot.
     
  5. Jeffman

    Jeffman Lieutenant

    Messages:
    591
    This happened to me a few times. Something like the following should work:
    Reflash the map. Then wait 20 seconds after the flash has ended. Turn off ignition. Wait another 20 seconds. Pull key and wait another 20 seconds (completely off). Then put in key and wait 20 seconds. Turn on ignition but don't start. Wait 20 seconds. Turn off ignition. Wait 20 seconds. Finally turn on car.
     
  6. JSR1256

    JSR1256 Private

    Messages:
    39
    Location:
    37922
    Very common right after a flash, do pedal trick as mentioned before starting car
     
  7. doublespaces

    doublespaces Administrator

    Messages:
    5,965
    Location:
    AZ
    Ride:
    2009 E93 335i
    I've never had my car do this by just flashing, but if I reset the throttle adaptation and don't give the car a moment to initialize it or something before turning the car on, then it goes crazy. It actually says to let the car sit for a bit after you've flashed, its a sub note below the success message I believe.
     
  8. Jeffman

    Jeffman Lieutenant

    Messages:
    591
    Correct.
    The oscillating 1000-2000 rpm idle occurs if you reset throttle adaptations and start the car immediately.
     
  9. matreyia

    matreyia Sergeant

    Messages:
    393
    Ride:
    335i e93
    MHD specifically warns everyone to turn off the car, then re-insert the key and turn on the ignition without starting the engine and wait 30 seconds before starting the car. This is done every single time you reset throttle adaptations. Otherwise, you will get a heart attack and think you messed up your car.
     
  10. R.G.

    R.G. Lieutenant

    Messages:
    564
    Location:
    Henderson, NV
    Ride:
    E92 N54, F02 N54
    Yea this has happened to me a few times. Pedal reset fixes it. I remember Tony V. freaking out in a post when it happened to him for the first time, lol! Another strange occurrence is immediately after a flash the car starts in 3rd and gives a nice "you broke something dumbass" sound if put in reverse. Letting it idle for 3-4min resolves as does driving to ~30mph or roughly wherever 3rd starts and it will shift down to 1st again.
    That's been an issue for me since Cobb days years and years ago.
     
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