After releasing gas pedal. I still hear the engine revving up for seconds

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Humailesh, Aug 8, 2015.

  1. Humailesh

    Humailesh Junior Member

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    After stepping over gas pedal revving up, when I release the gas pedal I can hear the engine revving up some more instead of slowing down.

    When I release the pedal, the engine is still making the noise as if I am stepping on the gas harder for about 3 seconds. when this happened, EV mode will be always not available, and gasoline consumption is increased. Getting lower MPG.

    Can anyone give an advice
     
  2. bisco

    bisco cookie crumbler

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    it's charging the battery, no worries.
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    I do not know, that seems odd. I've never noticed anything like that. Get it checked out, maybe have a dealership mechanic go with you on a test drive? Even better would be to also drive a dealership's demonstrator vehicle, for comparison.

    ( back from our road trip btw :))
     
  4. Humailesh

    Humailesh Junior Member

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    It is not charging the battery. This happens even if the battery almost full
     
  5. bisco

    bisco cookie crumbler

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    whoops! sounds like you'll have to read the codes. do you have a mini vci?
     
  6. bisco

    bisco cookie crumbler

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    how many miles on her? maybe the throttle body and mass air flow sensor need a cleaning.
     
  7. Humailesh

    Humailesh Junior Member

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    No I don't have it
     
  8. Humailesh

    Humailesh Junior Member

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    It has about 117k miles
     
  9. Humailesh

    Humailesh Junior Member

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    Recently, I have noticed that this issue comes up during hot days. I assume that there is a relation.
     
  10. Alesf76

    Alesf76 Member

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    Sure there is a relation: when you lift the foot from the throttle the car starts braking a bit, simulating the engine braking of a normal car. Under normal conditions it uses regenerative braking. But if the battery is full or too hot it uses engine braking like when you put in B and ICE revs up.
     
  11. Humailesh

    Humailesh Junior Member

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    Do you mean this is normal ?
     
  12. HTMLSpinnr

    HTMLSpinnr Moderator
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    The rev hang you describe happens when the battery ECU is protecting the battery when it's too hot. I notice this when my battery temps are somewhere above 46°C/115°F. You get very little hybrid assist, no regeneration, engine rev hang, and persistent idling.

    The engine slowly revs down instead of being quickly spun down through generation. It is using fuel during this process. The advantage here, is that power is almost instantly available if you need to accelerate again, vs the slow and painful wait for the engine to spool up again in this mode.

    I'm on my 7th summer in my 2010, and the past 2 summers have been the worst for this. I'm actually quite frustrated by the phenomenon, despite understanding why the ECU is protecting the battery.
     
  13. Piotrus Pan

    Piotrus Pan Member

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    Before the summer I got an update that causes similar behaviour. When I rev the engine it slowly turns off. If I keep pressing the gas pedal but keep in the EV part it turns off even slower. I would guess it's to lower the number of start/stop cycles of the gas engine.
     
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