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Consistent cylinder misfire

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Theman414, Nov 27, 2014.

  1. Theman414

    Theman414 Junior Member

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    I have a 2012 prius 2 that since day one has had a misfire issue that both toyota and myself cannot figure out.
    Some backround info; it only does this during and throughout winter months
    It happens at random after sitting overnight and getting cold, though not every time
    Toyota has replaced the intake manifold and gasket per a factory tech bulletin, misfire continued
    I have replaced all spark plugs with factory Denso plugs and it continues.
    I have ran heet and sea foam through system to attempt to both clear out water and clean injectors
    I also use only 91 octane or higher fuel in the car
    Originally the OBD system read misfire cylinder 1 today it did it again only now the scanner says pending misfire cylinder 3 and 4, and random misfire detected.
    Originally when the scanner was reading misfire cylinder 1 i swapped around ignition coils from cyl 1 and 2 and since then the last sentence is what has recently happened.

    Toyota has been no help and I am just tired of the problem, please if someone can help me I would greatly appreciate it.
     
  2. spiderman

    spiderman wretched

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    Plug wires replaced?
     
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  3. Jonny Zero

    Jonny Zero Giggidy

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    Lemon law it?
     
  4. Paradox

    Paradox Prius Enthusiast / Moderator
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    Moved to the appropriate forum
     
  5. Theman414

    Theman414 Junior Member

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    No wires on it, coil for each cylinder

    Couldnt lemon law it because toyota stopped making attempts once they couldnt get it, and I needed them to make 2 more before I could even try that
     
  6. Tande

    Tande Active Member

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    More info. please......under what conditions does this occur?......any & all?.....or is there a pattern?......just trying to relate this to my own situation......:confused:
     
  7. bisco

    bisco cookie crumbler

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    this is a known problem, and many threads here about it. there is no fix, the best you can do is let the car go through the complete warm up cycle every time you start it, before shutting down.
     
  8. Theman414

    Theman414 Junior Member

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    The conditions are always that the temp is below 30 degrees and the car has sat outside all night
    The condition never occurs in warmer weather, but to that point it also doesnt occur every time i leave it out
    No current discernable pattern but i was able to somewhat change the condition slightly when i moved the coil packs between cyl 1 and 2.
    Originally it only misfired on cylinder 1 but after i moved the coil packs it changed to random and cyl 3 and 4
    I thought maybe the coil but it didnt stay with the pack from cyl 1 and in my experience if a coil is going it will usually follow that coil and remain somewhat constant. I could be mis interpretting that though
     
  9. GregP507

    GregP507 Senior Member

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    Maybe the higher octane fuel is the problem. It's designed to be used in high-compression engines where pre-ignition (premature ignition) is likely to occur. The Toyota Atkinson-cycle engine is not designed for higher-octane (Premium) fuel. Try Regular and see what happens.

    Reasons why NOT to use PREMIUM GAS in your Prius | PriusChat
     
  10. GrumpyCabbie

    GrumpyCabbie Senior Member

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    Water in fuel? Do you leave the tank half empty a lot of the time? Where do you fill up? Tried going somewhere else? Is the petrol of a high(er) ethanol content? Where do you park overnight in cold weather? In a garage?

    Same engine, same car, yet the only fuel we get in Europe is the higher octane stuff or higher. I've had the engine misfire about 2 or 3 times when the car was about a year old and the problem was resolved after a service bulletin.
     
    #10 GrumpyCabbie, Nov 27, 2014
    Last edited by a moderator: Nov 27, 2014
  11. GregP507

    GregP507 Senior Member

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    Admittedly, 91 is only a few points over 87-regular, which is what I use, but there's nothing better about it that I can tell.
     
  12. Theman414

    Theman414 Junior Member

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    I have used all types of fuel both regular (87) and high octane (91 to 93) amd both no ethanol and a max of 10% ethanol blends, no change
    I have also gone to different places/companies for fuel and no change. I store it both in a garage when i am home and it sits outside at my job in an open lot and it hasnt shown to make a difference. I do my best to keep the tank full during winter months to avoid fuel line freeze up.
    I have tried running heet and sea foam through it to eliminate that possibility the best i could. I should add that this only happens on startup not at any other time. If i shut it down while it is misfiring and start it again it does stop misfiring at that moment.
     
  13. Easy Rider 2

    Easy Rider 2 Senior Member

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    Even though there is close to a ZERO percent chance that it will help this problem.........why not.

    Is it safe to assume that the plugs have been changed somewhere along the line ??
    I think you may have a "carbon path spark fault" that only shows up when the engine components have some accumulated moisture from the overnight temperature drop.
    That kind of problem usually happens on "rubber" parts of the spark path........but can also happen on the porcelain plug top too.
     
  14. GregP507

    GregP507 Senior Member

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    He said he changed the plugs. It's up to him if he wants to try different gas.
     
  15. Easy Rider 2

    Easy Rider 2 Senior Member

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    Well.......I think that kind of puts things in a different light.
    Are you SURE that there is a real misfire or is the engine just "running rough" ??
    I ask that because there could be a power imbalance among the cylinders because of something like a sticky valve (or an electrical fault if the valves are electrically operated) which would not constitute a "real" misfire.
    Bottom line: You should have been talking to Toyota corporate a LONG time ago and should do whatever you NEED to do to satisfy the basic requirements for creating a "lemon" case.
     
  16. Theman414

    Theman414 Junior Member

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    I did log a complaint with toyota USA as soon as the dealer said it was fixed after they replaced the intake manifold. I will visit that again
    When the event occurs that it logs a misfire the entire vehicle shakes which is what toyota says was the symptom of the previous manifold.
    I have changed the plugs and thoroughly gone through the coil pack connections and harness. I have also checked all injector connections and resistences of their coil.
    That doesnt rule out a sticking injector though
     
  17. Easy Rider 2

    Easy Rider 2 Senior Member

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    The really odd thing though is that you can make it disappear at will with a re-start.

    THAT should be a significant clue for any real mechanic who really understands how the whole system works........but that person might not exist outside of Toyota engineering.
     
  18. Theman414

    Theman414 Junior Member

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    VVT system issue?
     
  19. bisco

    bisco cookie crumbler

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    classic unburned fuel symptom that many, many here have complained about for some, the new mani worked, for others, not so much. don't start the car and shut it down before it has finished the warm up cycle.
     
  20. Theman414

    Theman414 Junior Member

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    The thing though is it misfires at the first start. If i immediatly shut it down and restart it the misfire is gone. But that unburned fuel statement makes me wonder if one injector could be leaking raw fuel during the off time of the car. Though the pressure drops there is still fuel on the rail. I wonder if that is making its way onto the valves from an injector leaking by