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Jerking when the fuel engine turns on

Discussion in 'Gen 4 Prius Main Forum' started by rahmani, Mar 10, 2021.

  1. rahmani

    rahmani Junior Member

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    Dec 13, 2020
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    Location:
    Bangladesh
    Vehicle:
    2016 Prius
    Model:
    Base
    While in park mode, usually the car is in electrical engine but when the fuel engine turns on, my car jerks a little while turning on after wards there’s just a little noise of the engine running but no jerking. Is it normal?
     
  2. priusman09

    priusman09 I used to be a TDI

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    Vehicle:
    2009 Prius
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    N/A
    This was normal in my 2009 over the 225,000 miles I had it. On my 2017 Prime it is less noticeable. It usually happened when I was sitting for long periods with the air on and the engine finally kicked in to charge the battery on the ‘09.
     
    rahmani likes this.
  3. jdenenberg

    jdenenberg EE Professor

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    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    Our Prii (I have had three) implement "neutral" using software control of the MG opposite the Engine on the Hybrid Synergy Drive. That MG is controlled to spin in reverse to compensate for the engine running forward so that the torque applied to the drive shaft is minimal. This is not perfect and when transients occur (like the engine starting up which requires some counter torque to spin the ICE), some torque is momentarily applied to the driveshaft and you will feel some movement.
     
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  4. rahmani

    rahmani Junior Member

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    2016 Prius
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    Base
    Thanks

    Thanks
     
    #4 rahmani, Mar 22, 2021
    Last edited by a moderator: Mar 22, 2021
  5. ISFdude

    ISFdude New Member

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    Location:
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    Vehicle:
    2017 Prius
    Model:
    Two
    I have a 2017 Prius 2 and Yes mine moves forward about 2 or 3 inches when the engine fires up and it’s a normal thing as it’s been doing this for awhile.
     
  6. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
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    IV
    I've noticed for my Gen 3 they actually made the ECM coordinate with the brake ECU. When it is about to start the engine and it's parked, it applies the brakes first, to minimize any roll of the car. If things are quiet enough, I can hear the brakes apply, and pretend I have precognition of when the engine's going to start.

    I don't know if they added that only in Gen 3 or if Gen 2 did it too. I know my old Gen 1 didn't.
     
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  7. Pulse07

    Pulse07 Active Member

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    2020 Prius
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    XLE AWD-e
    Is the parking brake on?
     
  8. Ramo_958

    Ramo_958 Junior Member

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    Vehicle:
    2018 Prius
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    One
    One of the cylinders might misfire.
     
  9. Chris Wolfgram

    Chris Wolfgram Active Member

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    You could at least wait until you get home to do that ! :) lol