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Engine Knocking/Shaking During Startup on 2012 Prius

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by sa177, Sep 4, 2012.

  1. sa177

    sa177 Junior Member

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    I know that there have been issues with 2010+ Prii with cold engine startups, but my 2012 Prius has had two episodes of the same thing that people have posted and that lastest episode was just a few hours ago and it wasn't even cold, 70+ degrees.

    Have any other 2012 Prius owners experience the same thing? The knocking and shaking happens right when the ICE kicks in after I started up the car and then goes away in about 5 to 10 seconds or when I changed gears on the car.

    Any advice would be helpful!!! The car is almost 7 months old and has 12,200+ miles.
     
  2. rrg

    rrg Active Member

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    I have the 2011.
    You would think the 2012 would come with the new TSB part applied to correct the old problem. Strange?

    I my experience last winter I used the Heet additive every other gas tank and I never experienced it again. The winter was mild on the east cost so that must of helped. I also tried to use the medium, or high grade octane gas.

    I'm at 20K miles and it only happened 2 times on cold days. This happened after I did not allow the warm up cycle to finish the night before.

    Maybe bad gas or water from condensation in the system?
    Keep us posted with what you find out or try.
     
  3. spiderman

    spiderman wretched

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    The '12s should have the new intake manifold design, so shouldn't have the problem. :(

    How would you describe the humidity at the time of the episode?
     
  4. sa177

    sa177 Junior Member

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    I don't know if it was because of me washing my car, but I washed my car and was hosing all the dead bugs off the front grill and then parked in the garage yesterday. Then, when I started the car last night, that was when the episode of knocking/shaking occured. It was the strangest thing.
     
  5. sa177

    sa177 Junior Member

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    I had no knocking/shaking this morning when I started the car.
     
  6. rrg

    rrg Active Member

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    So it went from the drive way, where it was washed, then you moved into the garage a short distance?
    The ICE never warmed up and shut off on it's own, if this is true.
    my2cents.
     
  7. sa177

    sa177 Junior Member

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    So after I washed my car on the driveway, I moved it into the garage. Then it sat there for a few hours and then I powered the car up, when the ICE kicked in to warm up, that's when the knocking and shaking event happened. I then changed the shift to Neutral and then the engine stopped knocking/shaking. I turned off the car, wait a few seconds and turned it back on again. The ICE seemed normal after that.
     
  8. spiderman

    spiderman wretched

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    Welcome to the knock club. :)

    I would report it to the dealer though so that they can document it. There is a slight possibility it left a code they might want to diagnose.
     
  9. sa177

    sa177 Junior Member

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    I'll set up an appointment and keep you guys updated. So sad that a new car would have these issues!!!
     
  10. spiderman

    spiderman wretched

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    One other member reported bad gas from BP was the cause, BTW.
     
  11. sa177

    sa177 Junior Member

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    My last fill up was from Chevron.
     
  12. jim256

    jim256 Member

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    I've found that if I let the car warm up to the point of ICE shutdown after washing the car with a cold engine, the rough start won't occur.
     
  13. rrg

    rrg Active Member

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    When in doubt, let it warm up. =)
     
  14. car compulsive

    car compulsive Active Member

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    The only time I have start knock is when I forget and DON'T do this. I've learned to just let the car run for a few minutes unti the ICE shuts off if I need to move the car around the garage / driveway. I try to plan ahead so I don't need to move the car short distances. If I'm going to wash it, I leave it outside and then use it for an errand after washing the car. I also keep it on the side of the garage opposite my tractor so I don't have to move it to mow the lawn / plow the drive.

    All vehicles have quirks. While this is annoying and possibly damaging to the engine, it seems that it can be avoided.
     
  15. Fred_H

    Fred_H Misoversimplifier

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  16. sa177

    sa177 Junior Member

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    Thanks!
     
  17. sa177

    sa177 Junior Member

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    I brought the car in today and it took them about 4 hours to evaulate. They said the car had no issues. So I guess I just have to watch and notate if there are any more hitches with this knocking event. Hopefully it won't ever happen again!
     
  18. rrg

    rrg Active Member

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    That is a very typical dealer response. Once the manifold clears up and the car stops shaking all sensors appear to respond normally by the time you bring it in. That's why the dealer can't find anything.

    The TSB is only being done if the dealer can actually see it happen. Some dealers are nicer and take your word for it along with a video recording of your car shaking.

    Since you are new to the car and now know what to look for, be more aware of it when the temperature drops.
     
  19. sa177

    sa177 Junior Member

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    I'll try to record each startup on my car to see if it happens again. I'm now wondering if I should get the extended warranty.
     
  20. zebelkhan

    zebelkhan Member in good standing

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    Chances are some water spray got inside and caused engine misfire for a few seconds, but not long enough to throw a code. I would not sweat it if I were you.