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Misfire on cylinder 1

Discussion in 'Gen 3 Prius Main Forum' started by Dmmfox15, Jul 29, 2019.

  1. Dmmfox15

    Dmmfox15 Junior Member

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    ok so a while back out 2010 Prius started running rough. We replaced the egr valve and cooler, the sensors and the plugs and coils it is running much better but we still have a intermittent issue and the code reader says misfire on cylinder 1 anyone have suggestions on how to resolve this?
     
  2. Raytheeagle

    Raytheeagle Senior Member

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    Welcome to Prius Chat (y).

    Some questions:
    • How many miles on your Prius?
    • Is the engine coolant level stable?
    • Did you clean the intake manifold when the egr cooler and valve were replaced?
    Good luck and keep us posted (y).
     
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  3. Dmmfox15

    Dmmfox15 Junior Member

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    There are 224000 miles on the car yes the intake Mansfield was cleaned at this time
     
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  4. bisco

    bisco cookie crumbler

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    have you done a compression check?

    how much oil does it burn?
     
  5. BZzap!

    BZzap! Senior Member

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    There are many, many reason why a misfire can occur. This is especially true in your case with your car having this very high mileage on the clock. A comprehensive diagnosis is the only true way to uncover the problem. Unfortunately, there are very few shops that you can trust to do this without paying a huge chunk of money. Your problem is probably going to be finding a good honest shop. Star by looking around for a reputable repair facility that has good customer feedback.
     
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  6. Austin Longenecker

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    I'd consider doing an engine coolant flush & replace even if the coolant is steady. Mine was steady, just a little low, so I changed it when I had similar issues to you, and like you, after having the EGR cleaned or replaced. The coolant flush completely eliminated the misfiring 100%. Its never returned since.
     
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  7. The Critic

    The Critic Resident Critic

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    That makes zero sense. How does a coolant replacement fix a misfire?
     
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  8. bisco

    bisco cookie crumbler

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    old coolant = bad karma?
     
  9. Raytheeagle

    Raytheeagle Senior Member

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    Old coolant = pH imbalance

    pH imbalance = less protection

    Less protection = potential problems
     
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  10. Dmmfox15

    Dmmfox15 Junior Member

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    No we have not done a compression check
    and before all this it burned some oil but I understand that was an issue with this year prius
     
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  11. bisco

    bisco cookie crumbler

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    not all of them, but some number typically start burning around 100k when the egr system clogs
     
  12. CR94

    CR94 Senior Member

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    Which is first? I'd guess it's more likely that burning contributes to clogging than vice versa. Or are those independent maladies?
     
  13. bisco

    bisco cookie crumbler

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    i don't think there's any consensus among the experts. your guess is as good as anyones. we'll probably know more as the 14's and 15's get up there, with the improved rings and pistons.
     
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  14. Austin Longenecker

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    Honestly, I'm not entirely sure, but it immediately fixed the problem. Not to say correlation is causation, but all the arrows say that that's what fixed my misfiring.
     
  15. The Critic

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    When the coolant flush was performed, did someone add type of "cooling system conditioner" or "cooling system stop-leak" as part of the coolant flush service?

    If they added an additive of that type, it would explain why your misfires stopped (assuming you had/have a leaking HG issue).
     
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  16. Austin Longenecker

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    Nope, I flushed it myself and did nothing other than remove the old fluid and refill it with new fluid. It worked so that's all I cared about.
     
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  17. ifty1989

    ifty1989 Junior Member

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    I had the same problem. But I was getting a misfire on cylinder 3. Turned out to be the inlet manifold blocked on number 3. Cleaned it out and havnet had a problem since.

    Posted via the PriusChat mobile app.
     
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  18. Mendel Leisk

    Mendel Leisk Senior Member

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    At what miles was that work done? Maybe it's closing the barn door after the horses have already bolted: if you wait on cleaning the EGR system till the car's running rough, the engine's been running at elevated temperature for a long time: a easy-flowing EGR is instrumental in keeping combustion chamber temperatures down.
     
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  19. RacerNate

    RacerNate Junior Member

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    Hey first post!
    Toyota has a service Modification for this issue.
    First the wires running to the EGR need to be untapped from the main loom.
    NOT THE WHOLE WAY, just where they pulled them backwards.
    Then rewrap the main loom and the EGR wires separated.

    Hope this helps
     
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  20. voxbox

    voxbox Junior Member

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    Hey RacerNate, I have a similar issue, can you send me the number of the service bulletin so that I could look it up? I took it to Toyota today but they could not figure out what's wrong (attached) mine has 127k miles.

     

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