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“Lurch”/Rough Feeling when Gas Engine Starts While Driving

Discussion in 'Prime Main Forum (2017-2022)' started by PeninsulaPrime, Dec 29, 2021.

  1. PeninsulaPrime

    PeninsulaPrime Member

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    Sometimes my 2021 LE, 27k miles, will be at the edge of exhausting the battery in EV mode and then turn the gas engine on.

    Sometimes, particularly when it’s cold and the first start of the day, it feels kinda tough. Like hitting a very small pothole or patch of rough road. There is definitely a perceptible switchover and something more mild than what I’d call a lurch.

    How normal is this?
     
    #1 PeninsulaPrime, Dec 29, 2021
  2. jerrymildred

    jerrymildred Senior Member

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    Very. Throttle mapping in EV and HV are quite different, so I'm actually surprised at how often it's smooth.
     
    #2 jerrymildred, Dec 29, 2021
    Ovation likes this.
  3. PeninsulaPrime

    PeninsulaPrime Member

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    For sure, you can definitely feel the mapping change as HV kicks in - but that's much smoother than what I'm talking about.

    For me, the lurch/bump happens exactly as the engine starts and doesn't gradually phase in like the throttle mapping change over 1-2 seconds. It's not that bad but my wife also felt it was a little rough. Kinda worried about it getting worse.
     
    #3 PeninsulaPrime, Dec 29, 2021
  4. bisco

    bisco cookie crumbler

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    hard to diagnose over the internet because there is some. but how much is subjective. any way to test drive another?
     
    #4 bisco, Dec 29, 2021
  5. jerrymildred

    jerrymildred Senior Member

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    I think what you're feeling is a torque reaction. To start the ICE, MG1 spins it to 1,000 RPM. That sudden change in inertia rocks the engine, which you feel as a lurch. Once the ICE is running the torque is pretty constant, but that sudden change from zero to 1,000 RPM is very noticeable.

    My 2017 has done this since I owned it. My 2013 PiP did it. My wife's 2017 Prius does it. And all three of our Gen 2s had that little lurch when the ICE started.
     
    #5 jerrymildred, Dec 30, 2021
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