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Strange behavior when stopped in gear with brakes

Discussion in 'Gen 2 Prius Main Forum' started by JoelB, Jan 27, 2019.

  1. JoelB

    JoelB Junior Member

    Joined:
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    2007 Prius
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    II
    The more i drive my prius the more "in tune" i get with its function. I'm having trouble noticing whats normal for a hybrid and what could be signs of an issue.

    My current question is about when the car is in gear with the ICE on and being held in place by the foot brake. I'm feeling a pulsing feeling for lack of a better term. The pulsing is maybe about once a second roughly and doesn't always happen. It goes away fully when the ICE turns off. In normal operation the brakes feel smooth and seem to stop well. Is this some sort of issue? Am i even describing this decently??

    Thanks everyone for your help so far. This has been an interesting learning opportunity owning this car.
     
  2. kens97uber171

    kens97uber171 Active Member

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    Is the pulsing coming through the brake pedal? Or do you just feel it in the car like the engine is causing the pulsation. possible you might have a slight misfire going on although I would think that would set a code. I personally have noticed in the winter time that the gasoline engine is a bit more erratic. It runs for a variety of different reasons, keeping the exhaust hot so that the catalytic converters operate as they are supposed to. keeping the engine coolant warm enough so that the cabin temperature stays warm enough. And then the other hybrid functions such as keeping the battery at the proper charge Etc. During the summer months those first two items occur less often because of the higher temperature. The car definitely is more erratic in the winter and as these cars age you always have the possibility of a little bit of wear and a motor mount, a slight misfire because of age or a malfunctioning coil or a bad spark plug. one of the thing I have noticed is when you're stopped at a light with your foot on the brake if you look at the energy monitor you may notice that power is still coming from the battery to the wheels while you're stopped. If you press the brake pedal a little bit harder it will stop doing that. That could be what's causing it although you mentioned that it discontinues the pulsation wants the gasoline engine stops.
    you can eliminate the cabin temperature being the reason for the engine running by turning the climate control completely off oh, nothing much you can do about the car wanting to keep the exhaust hot. You might pull the plugs see if they look okay, coil pack failure is something that can happen but normally it's not as mild of a failure as you're talking about it would be more dramatic of a misfire and certainly would throw a code. You could also try putting some seafoam into the gas tank maybe you've got a slightly clogged fuel injector. Sorry I'm kind of being all over the place in my explanation here I'm just writing stuff down as it comes into my mind. Good luck with it let us know if you discover any other behaviors that may give us more information.

    Posted via the PriusChat mobile app.
     
  3. bisco

    bisco cookie crumbler

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  4. jerrymildred

    jerrymildred Senior Member

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    It weird, but it's normal. The Prius has several stages of warmup. In stage 3 the engine is reluctant to shut off at a stop and will often shudder. To me, it felt like a gentle nudge in the back bumper. There's a detailed explanation here:
    The Five Stages of Prius Hybrid Operation | PriusChat
     
  5. JoelB

    JoelB Junior Member

    Joined:
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    Location:
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    Vehicle:
    2007 Prius
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    II
    Thanks everyone. I'll be reading that post today at some point. It will be good to know a little more about the phases the car is going through as i drive.
     
    jerrymildred likes this.