Car knocking, changed spark plugs, problem persists

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Jacob Bonner, Feb 7, 2019.

  1. Jacob Bonner

    Jacob Bonner Member

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    So I've had a knocking sound for the past several weeks. I replaced the spark plugs but that did not take care of the issue. Today, while knocking, the engine light came on so I had it plugged up to read the code and it read that the 2nd cylinder is misfiring. I'm considering replacing the ignition coil next (a $80-100 fix), but I've seen videos on YouTube of people just replacing the boot (a $10 fix) and that solving the problem. I can do the work myself, but what I am not sure about is how to go about finding the specific boot replacement. As far as I know, the ignition coils are original.
     
    #1 Jacob Bonner, Feb 7, 2019
    Last edited: Feb 7, 2019
  2. tankyuong

    tankyuong Senior Member

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    I would replace the whole coil
     
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  3. NutzAboutBolts

    NutzAboutBolts Senior Member

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    Swap the ignition coil to see if it persist
     
  4. Raytheeagle

    Raytheeagle Senior Member

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    How many miles on your Prius?

    Ever clean the egr circuit?

    Install an oil catch can?

    Good luck and keep us posted (y).
     
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  5. Jacob Bonner

    Jacob Bonner Member

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    It's a 2012 and has 173,000 miles. I've not cleaned the EGR valve since I've owned it (I bought it at 154,000 miles in 2017). It does not have an oil catch can that I am aware of.

    As for ignition coils, are there preferred brands? If looking at brands like Delphi, Denso or NGK they are about $90 a piece. However, on eBay I'm seeing them in the $40 range for complete sets, but this seems suspicious to me... I'd certainly love to save money, but I don't want to put junk in my car either.
     
  6. Raytheeagle

    Raytheeagle Senior Member

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    I’d start with an egr circuit cleanse before doing any purchasing of new coils ;).

    That’s essentially free (other than your time) unless you will be buying new gaskets.

    Good luck and keep us posted (y).
     
    #6 Raytheeagle, Feb 9, 2019
    Last edited: Feb 9, 2019
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  7. frodoz737

    frodoz737 Top Wrench

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    Similar to post #3...swap #2 COP with another position and see if it follows first.
     
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  8. Jacob Bonner

    Jacob Bonner Member

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    So last night (30 degree weather), I was driving to town and had the heat on (it takes a lot longer to heat up the car than it use to - now it takes a good 15 minutes to feel any warmth, at least), the coolant temperature warning light came on. The coolant level is slightly lower than it was when I filled it to the full line about a week ago (though it was warmer when I filled it). It's still just above the low line (it's awfully difficult to see between the full and low line, due to the casing.. not sure why they did it like that). Perhaps I have multiple problems? I'm looking up videos on EGR cleaning.. will update everyone when I finish that. I'll also look into an oil catch can at some point. Will change the ignition coil if EGR cleaning doesn't work. Thanks
     
  9. Raytheeagle

    Raytheeagle Senior Member

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    The coolant light coming on is a bad sign:(.

    Do you have a way to monitor engine temps? To me (based on your description), it sounds like the thermostat and or the water pump are bad;).

    I’d mark the level for your future reference to ensure it isn’t losing coolant as that’ll signal a much larger issue(y).
     
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  10. Kenny94945

    Kenny94945 Active Member

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    FWIW...I did not read where the OP stated the knocking was at idle, while cruising,
    or under load.

    Does state there was a computer code for cylinder two misfire.

    OP changed their spark plugs.

    Car has about 175K mileage.

    1) Did cylinder 2's spark plug look like the other 3?
    2) Typically knock is timing issue and can be related to octane/ fuel quality.
    Can also be related to excess carbon build up in the combustion chamber.
    3) Cleaning the ERG is a know Prius maintenance procedure...best guess.
    4) Swapping coils to see if the computer code swaps to another
    cylinder is also best diagnostic advice.
    5) If trying to save money, can a single spark plug wire be purchased?
    In other words, maybe a wire and not the coil.
    6) E-bay clone coils for $40 a set vs. name brand at $90 each.
    I don't know to say other than if it was me, I would replace with OEM Toyota.

    Good luck.
     
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  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    There coils are right at the spark plugs, no wire.
     
  12. Salumi

    Salumi Junior Member

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    Hello bonner
    What year is the car
    And is antifreeze reducing too ??
     
  13. Jacob Bonner

    Jacob Bonner Member

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    It is a 2012. I just checked the coolant levels and it has indeed dropped (about an inch and a half below low line) since I topped it off about a week ago (although it is night and I'm shining a light on it - visibility is low).

    I put my brother's code reader on it the other day and it has P0300, P03001 and P03002, so apparently it is more random rather than localized (O'Reilly's, earlier, told me it was the 2nd cylinder). The coolant temperature light has not come on since, though it still takes a long time to heat. I've not cleaned the EGR yet as I am a full-time student + working, so I do not have much time to devote to this.

    Not sure if it's worth noting but since November or December of 2018 I've been using Top Tier gas from Shell. The knocking issue began in late January. I wouldn't have thought that would be related, but it's still worth mentioning nonetheless.
     
    #13 Jacob Bonner, Feb 23, 2019
    Last edited: Feb 23, 2019
  14. Jacob Bonner

    Jacob Bonner Member

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    I checked my oil to see if there was any mixture of coolant. From looking at the dipstick, it looks normal to me. I'll have to investigate further in the morning, to see where the leak is at.
     
  15. Raytheeagle

    Raytheeagle Senior Member

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    If the coolant level is dropping, the head gasket is done:(.

    You’ll have to deal with it as it will only get worse and that is the cause of the knock you are experiencing ;).

    Where is the US of A are you located :whistle:?

    Good luck and keep us posted (y).
     
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  16. Mendel Leisk

    Mendel Leisk Sand Pounder

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    leak down test to confirm?
     
  17. Jacob Bonner

    Jacob Bonner Member

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    Wouldn't the fact that the oil on the dipstick is not milky indicate that perhaps the leak is elsewhere? I wish I knew exactly when the coolant leaked. Sometime in the last week.

    If it is -- how difficult is it to replace a Prius head gasket on your own? I can't pay 2-5k for repairs.
     
  18. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Good video here. There's some extra prep steps, removal of the wipers/cowl, engine underpanel, wheel well liners. Also, I'd be inclined to clean items like the valve cover before taking it off. But anyways, interesting, and lots of tips:

     
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  19. Jacob Bonner

    Jacob Bonner Member

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    Update: I just ran a block test on the coolant system and the liquid did not turn yellow, so I am assuming then that the head gasket is okay? Seeing as how you can't continuously run the engine on a Prius, as the block test directions call for, I just put the heater on full blast and ran through 3 engine cycles and then performed the test for another 2/3 cycles. I guess now it's just a matter of finding where the coolant leak is precisely.

    I'll clean the EGR valve and cooler and see if that resolves the issue.
     
    #19 Jacob Bonner, Feb 24, 2019
    Last edited: Feb 24, 2019
  20. Mendel Leisk

    Mendel Leisk Sand Pounder

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    At about 3:15 @NutzAboutBolts shows how to put the car in "maintenance mode", runs the engine continuously:



    Also outlined in attached:
     

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