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A loud, metallic start up sound from engine

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Yaggo, Sep 30, 2014.

  1. Yaggo

    Yaggo New Member

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    Any idea what caused the horrible start up sound in the video?

    https://www.youtube.com/watch?v=ub7dHPuX_eU

    The video description:

    A loud, metallic start up sound from Prius engine. The engine runs smoothly in the end of video, although that cannot be heard. The car was shortly moved in the previous day (shutting down the engine before warmed up). The tank contained E38 ethanol mixture. No "check engine light" came on.

    I'm not sure what caused the sound, maybe the "lawn mower syndrome"? (e.g. https://www.google.com/search?q=car+e...)

    The car was driven afterwards and everything was ok.

    Before you comment "ethanol destroys your car", there are plenty of people driving regular Prius with various ethanol blends without problems, so I don't believe that the sound was caused by E38 fuel alone (although it may have contributed).
     
  2. GrumpyCabbie

    GrumpyCabbie Senior Member

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    So does the manufacturer recommend E38? Nope. They say not to use anything more than E10. I think you know what's causing the noise :rolleyes:

    Some people have run a car with an accidental mix of diesel and whilst allowing the car to run, it will cause damage, mainly to the emissions systems. Same as E38. Some might say they use it fine, some might be exaggerating, some might live in a very warm climate etc. There is a member on this forum who uses E95 I believe, but he lives in warm Alabama. The car is designed to use E10 and you should use E10 or less. You might get away with E15 or E20 but you're slowly taking a risk.

    Try running with normal petrol and see if the noise goes away.

    And whilst I appreciate petrol is expensive in Finland compared to our American friends on here, but it is slightly cheaper than here in the UK. If you pay €1.60 that equates to £1.25 a litre, and presently ours is about £1.30. I assume E38 is cheaper but do you really need to save those extra few pennies enough to damage one of the Worlds most efficient production cars?
     
  3. Former Member 68813

    Former Member 68813 Senior Member

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    kenichols29 likes this.
  4. David Beale

    David Beale Senior Member

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    There is a "bug" in the 2010s that causes the issue particularly if the car is run for a very short time and then shut down cold. There is a fix (TSB) on this issue, involving replacing a manifold. Not sure if it totally fixed the problem. I've never seen it in Pearl S and I have run it for a very short time and shut it down cold. So perhaps the manifold change does fix it, as Pearl S has the newer manifold.

    I don't think it has anything to do with the E38, though you really shouldn't be using that fuel. The manual says E15 max. here in Canada as I recall though it could be E10.
     
  5. Yaggo

    Yaggo New Member

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    Thanks everyone for your answers. I've read about the "bug" David described and it seems to match (btw, it's not Prius-specific problem, e.g. some Volvo users have reported it as "lawn mower syndrome", you run the car shortly to take your lawn mower out of carage). After running the engine very short time, there must have been excessive fuel (with ethanol) in cylinders, probably cleaning the oil away and absorbing extra moisture, leading to very long start up time and noise because of dry cylinders. Of course this is pure speculation, I'm not a gas engine expert. What do you think guys, was there permanent damage caused to the engine?

    For you who think the ethanol is to blame, please read about this conversion Prius made by company selling waste-made E85 in Nordics: Toyota Prius Ethanol Hybrid | BSR

    Also, there is a German mpg-tracking website, where you can find people running Prius on ethanol, e.g.: Details: Toyota - Prius - III MC Lounge 17" - Spritmonitor.de

    While I agree that too much ethanol may shorten the lifespan of fuel components in the long run, it's widely known that regular cars can run on up to ~40-60% ethanol mixture even without a "box" (which just injects extra fuel, no magic here). That's why I don't buy the argument that my issue was caused solely by the E38 fuel (which was a mixture of 95E10 and 106-octane RE85 (brandname for waste-made E85)).
     
  6. Former Member 68813

    Former Member 68813 Senior Member

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    One more thing, your mystical "lawn mower syndrome" is simply a flooded engine. Very common in the era of carburated engines.
     
  7. CARspec

    CARspec Junior Member

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    The rattle is the sound of the car misfiring, which can be caused by a number of issues, and is unlikely to be related to the high ethanol content alone, simply because the vehicle does it off and on.

    Funny enough, they axed the "Replace intake manifold for misfire codes" bulletin back in April and left only the cold-start P0A0F bulletin intact.

    edit: the axed it for the USA, but the Canadian bulletin remains. Had to check TIS.
     
  8. dj2big

    dj2big Junior Member

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    Mine is a 2014 and I'm getting the knock using unleaded none E gas
     
  9. Metalman

    Metalman Member

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    We have a 2010 Prius and as was mentioned it will knock and hammer for several seconds at startup under certain conditions. It has done this when starting after being stored for six months. It has also done it when starting after having been shut down before the engine was thoroughly warmed. The Toyota dealer will do nothing about the problem unless they observe it. And since it happens so rarely, there isn't much chance of it happening for them.
     
  10. Rapid Dog

    Rapid Dog Member

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    I just had this happen this morning for the first time. I shut it off immediatly. Sounded like a wrench fell in the engine bay.
    Opened the hood, nothing to see here.
    Then started it again and watched as the engine shook like a wet dog and mad what sounded like a clutch coming apart.
    Any other discussions other the fuel about this?
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    What year's your car? Confused: you're showing 2005 V in info, but this is third gen forum.
     
  12. Rapid Dog

    Rapid Dog Member

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    My bad, I traded in the '05 for a 2010 certified. Haven't had one problem in 12K miles til this morning.
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