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Potential Solution to the Rough Start/Engine Rattle

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by FlyBoy2960, Feb 24, 2011.

  1. FlyBoy2960

    FlyBoy2960 New Member

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    I've been recently having the engine rattle/knock noise occasionally when I start the car. After my first oil change, I mentioned this to the dealer and demonstrated this to them while they documented the issue. I left my car at the dealership for investigation.

    The following day, my dealer said they called Toyota and created a case about this. Toyota responded saying they heard about this and the possible root cause is the Motor Mounts on the Prius. They will be sending parts (date is still unknown) to fix the issue. :rockon:

    I specifically asked if there is any damage to the engine and they said absolutely not and there is nothing wrong internally with the car. This also makes kinda sense because if I press the accelerator to the ground when it starts up, the knock doesn't appear. It also works if I put the car into D and drive away.

    For your information, I live in Eastern PA and purchased my 2010 Prius at a very large and popular Toyota dealer..oldest in the USA.
     
    #1 FlyBoy2960, Feb 24, 2011
  2. 32kcolors

    32kcolors Senior Member

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    We'll see if that surfaces as a TSB.
     
    #2 32kcolors, Feb 24, 2011
  3. bisco

    bisco cookie crumbler

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    if it's motor mounts, wouldn't it happen all the time?
     
    #3 bisco, Feb 24, 2011
  4. tumbleweed

    tumbleweed Senior Member

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    I was thinking the same thing.

    The special set of circumstances that can lead to a "rough start condition" are usually reported as:
    1. engine run briefly and shut down cold,
    2. wait several hours, usually overnight,
    3. restart engine.
    Even then it only seems to happen in cool to cold weather, hardly any reports of summer occurrences and it is not repeatable.

    The two "theories" that have been credited to Toyota are:
    1. that it is caused by MG1 being out of phase with the ICE, and
    2. the motor mount theory reported by FlyBoy2960.

    I don't think either of these "theories " explain the symptoms that have been reported on this site or the ones I have experienced with my car.

    I will be interested to see if new motor mounts will fix the problem and I hope they do, but I remain skeptical.
     
    #4 tumbleweed, Feb 24, 2011
    1 person likes this.
  5. spiderman

    spiderman wretched

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    Also VVT-i where is where I would put my $ if I was a betting type.
     
    #5 spiderman, Feb 24, 2011
  6. tumbleweed

    tumbleweed Senior Member

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    Yes I forgot that one, may be the best guess from Toyota so far. I still kind of like the left over fuel in the intake system though. They could be related?
     
    #6 tumbleweed, Feb 24, 2011
  7. The Critic

    The Critic Resident Critic

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    #7 The Critic, Dec 29, 2011
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