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Very short screech noise when ICE starts.

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by The Professor, Feb 12, 2019.

  1. The Professor

    The Professor Senior Member

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    When starting moving using electric (I think after a previous short warmup, but could be coincidence), I'll get to maybe 10MPH and the ICE then starts up. I suspect the engine is still not fully warmed up, as the ICE makes a slight shudder. This is all normal...

    However, towards the end of the shudder you feel when the ICE starts, the car makes a very short screech sound that rises in pitch, almost like the sound a tyre losing traction for 1/4 second would make. I've heard it several times in the last few days, but only once per journey and always close to the start of the journey the first time the ICE kicks in.

    Car runs normally, no error codes, etc. Just wondering what that new noise is.

    Any ideas?
     
    #1 The Professor, Feb 12, 2019
  2. booke02

    booke02 Active Member

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    Could be something mundane like a loose fan belt.
     
    #2 booke02, Feb 12, 2019
  3. kithmo

    kithmo Couch Potato

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    No belts on the Gen 4, sounds like you may have an air leak somewhere on the inlet side, one of the rubber tubes maybe ?
     
    #3 kithmo, Feb 12, 2019
  4. alanclarkeau

    alanclarkeau Senior Member

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    It never sounds quite the same - I rarely notice it if the car is warmed up, even listening for it.

    When cold, sometimes it's barely noticeable, other times that slight shudder with other accompanying noise, sometimes noisier than others - induction, exhaust, fuel and oil pump, VVT-i etc. If the engine is warm, the cooling fan and/or the water pump start. In your case you've got grille shutters as well as the exhaust heating recirculation mechanisms activating too.

    I've never worried that it's often different sounds. I always assume it's like starting any ICE. Besides the whirring of the starter motor, quite a few other sounds are noticeable on a "normal" car. The ICE on PRIUS, having been deep in sleep is awakened, spun over, fuel injected and she's expected to spring to life and instantly start climbing a hill or whatever. With no coffee. I'd do more than groan and squeak!!
     
    #4 alanclarkeau, Feb 12, 2019
    Al9003 and kithmo like this.
  5. GRich

    GRich Junior Member

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    Are you sure it's not the brake test. It makes a single soft squick noise around that speed

    "When the vehicle speed reaches approximately 20 km/h (12 mph), the initial check of the brake actuator assembly is performed and pump motor operation sounds are generated"

    Posted via the PriusChat mobile app.
     
    #5 GRich, Feb 27, 2019
  6. The Professor

    The Professor Senior Member

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    Yes, it could be that for sure, thank you.

    On further testing it seems to occur the first time I get to around that speed (even if the ICE hasn't come on yet). I was going to say 14MPH but of course the speedometer reads 1 or 2MPH fast in that range, so 12MPH is likely correct.

    I was also pondering if it could be the active shutters, as it does also sounds how you might imagine a long thin (i.e. shutter slat) shaped piece of plastic rubbing against something. But I'm sure I'm hearing it from towards the driver's side rear wheel... Again fitting with the brake test.
     
    #6 The Professor, Feb 28, 2019
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