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P0300 0301 0303 misfire and engine knock problem

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by noctiluca, Apr 10, 2020.

  1. noctiluca

    noctiluca Junior Member

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    Documenting what happens to help people in the future and would appreciate any feedback. There is a lot of info on here about this problem, and I suspect I'm having the comprehensive EGR system issues, but welcome any of your thoughts!

    Specs: 2014 Prius V, 130k miles, no coolant or oil loss.

    Symptoms: I bought the car second hand in January 2019 with 110k miles on it, and it was absolutely pristine and running like a dream. I've done a few long distance trips in a row, and on the last run from CA to Canada, I started to notice a barely detectable roughness.

    A couple weeks ago, it started a bit rough after sitting in the cold overnight. I assumed it was its age and colder temps than I'm used to. A few days ago, it misfired on the freeway and again on residential roads, but it was quick. It took a couple days for the engine codes to pop up, and I got P0300 (multiple misfire), P0301 (cylinder 1 misfire) and P0303 (cylinder 3 misfire).

    Treatment: The first thing I did was put HEET in just in case there was some condensation buildup. No change.

    Then I pulled the EGR pipe and cleaned it and the little intake to the intake and the intake to the valve. Car ran perfectly for two days, CEL went off on its own, and I thought I was golden. Today, the intense rattle is back.

    Plan: My plan is to thoroughly clean the intake manifold and valve/cooler first. I think I'll decide after I pull it apart whether I want to spring for the new models or just try to clean them. I'll probably check/replace spark plugs and clean the injectors, or maybe just use injector cleaner (I've had great luck with this stuff in the past).

    I'd love to hear from anyone if you have experience with this issue!
     
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  2. Raytheeagle

    Raytheeagle Senior Member

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    Definitely clean the egr circuit stem to stern;).

    Use a pressure washer to clean the egr cooler as it makes the cleaning process very easy:).

    Add an oil catch can and you'll be good to go(y).
     
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  3. Aaron Vitolins

    Aaron Vitolins Senior Member

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  4. jzchen

    jzchen Newbie!

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    Replace spark plugs?

    moto g(7) power ?
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Good (actually vital) preventative measures noted above. Still, where you're at, the head gasket might already be failing. The codes you've got often lead to that. You could try swapping coils (label them first), see if the codes follow. I think best bet for checking the head gasket would be leak-down test.
     
    #5 Mendel Leisk, Apr 11, 2020
    Last edited: Apr 11, 2020
  6. pjksr02

    pjksr02 Active Member

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    That's a good point. If one can clean the EGR system DIY, without much $ cost, cleaning and hoping for the best is an approach. But, if one will be paying for cleaning the EGR system, most likely a costly endeavor, checking the integrity of the head gasket first, by leak-down or scoping, makes sense.

    How well do misfire codes correlate to head gasket failure? It seems that recent history in PriusChat points to the head gasket being a common cause of misfire.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah moving the coils around is a free (DIY assumed) move to see what happens.
     
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  8. noctiluca

    noctiluca Junior Member

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    has anyone cleaned the case behind the PCV valve?

    she is now in pieces! spark plug in cylinder one was fuel fouled and all four seemed to be burning differently, the bottom of throttle assembly had some oily sludge in it (don't know what that means), and @NutzAboutBolts is my hero!

    ill have to wait until after egr system cleaning to check the coils, but it seems reasonable that one or more might be toast.
     
    #8 noctiluca, Apr 11, 2020
    Last edited: Apr 12, 2020
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  9. noctiluca

    noctiluca Junior Member

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    hey youre in the area! do you know where to source a reasonably priced oil catch can?

    also really f$@%ing hoping its not a head gasket. shes a bit short in the tooth for that and no fluid mixing or loss, but it seems like its inevitability at some point. since im doing work myself, im starting with EGR cleaning, spark plug/PCV valve replacement, and coil test, and will do a leak down after shes all put back together just for peace of mind (or not haha).
     
    #9 noctiluca, Apr 12, 2020
    Last edited: Apr 12, 2020
  10. noctiluca

    noctiluca Junior Member

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    that means the cooler>valve>pipe>intake manifold right? want to make sure im not missing anything!
     
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  11. Raytheeagle

    Raytheeagle Senior Member

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    Yes;).

    Then the oil catch can is separate :).

    But another good measure(y).
     
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  12. ChapmanF

    ChapmanF Senior Member

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    It's the usual dilemma: we would all learn the most if those things were done separately; if they're all done together and the problem goes away, no one will ever know what it was or which intervention solved it.

    But then nobody wants to spend too much time diagnosing an ailing engine. (Just like asking someone with a scary illness to participate in a blinded trial, though it's the only way we can learn what works.)

    Just have to wish you the best of luck with whatever way you're comfortable approaching it.

    On the effectiveness of in-tank injector cleaner versus other injector interventions, we have some data here.

    I wouldn't lose too much sleep over the gasket unless you acquire other evidence that suggests it. There's a folk belief here on PriusChat linking the EGR and gasket failures, very strongly held by those who hold it, but the explanations on offer never seem to get beyond 'truthiness', like,

    • "Well, the EGR goes through a cooler, so if it's clogged, duh, combustion is hotter and there goes your gasket!"
    • "Ok, truthy, but combustion goes from ?°C to ?°C and the gasket material limit is ?°C ?"
    • crickets

    It kind of stays forever in that perpetual limbo, while the unconvinced are sort of waiting to see better support and the convinced don't think any is needed.
     
  13. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Kudos to you for getting all of this done yourself. Hopefully cleaning all of this up, and maintenance gets you back on the road, running smooth as silk.
     
  14. noctiluca

    noctiluca Junior Member

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    Well, she's all back together now. So far so good on CEL through a few cycles but I'm not optimistic I'm done.

    The EGR valve had probably ~0.5cm of carbon deposits on it, same with the cooler, lots of areas of obstruction. The pipes were relatively clean and the intake manifold was relatively clean other than the small amount of pooled oil at the base. The PCV valve felt operational, gave it a shake and made the tell tale sounds. I replaced it anyways but I don't think that was the issue. The PCV valve hose that runs to the intake was a nightmare! It looked like it was full of mulch! Same thing on the inlet on the intake manifold side. Don't what that was, fibers of some kind. I'm sure it's fine ;)

    This job was pretty nasty because of a few precarious screws and nuts that attach the cooler. I dropped a screw and then had to remove the liner to get it, which was extra super duper frustrating. I had a large variety of tools to cope with the various squeezy spaces and I still had to sit on top of the engine to get to the back of the cooler, and my hands are shredded and bruised. Wasn't really the funnest job I've had to do. Probably easier for dudes to reach.

    I'm waiting for a misfire on one of the coils, and had to order the oil can so will have to get in there again shortly, but for now, she's not in pieces anymore and seems to be running well.
     
    #14 noctiluca, Apr 16, 2020
    Last edited: Apr 16, 2020
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    Did you get the small diameter EGR ports in the intake manifold? Sounds like you did, just wondering. Brushes designed for cleaning stainless steel drinking straws are good for that, with a little brake cleaner.
     
  16. noctiluca

    noctiluca Junior Member

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    yup definitely. they were all reasonably clean except for the one that goes to the PCV valve, but they all got thoroughly cleaned. should we be using brake cleaner on plastic? i realized after i had already done it that that probably wasnt very smart.
     
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  17. Mendel Leisk

    Mendel Leisk Senior Member

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    Brake cleaner is ok.
     
  18. HaYon Prius driver

    HaYon Prius driver New Member

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    I had this same issue on my 2013 toyota prius 2 at around 180k miles. It started as rough starts then the check eng light came on with the #1 cylinder misfire code. I changed the coil pack and all spark plugs they were do for replacement anyways. Check eng light went away and things seemed fine for a day. Rough start came back so I did what you have done. I cleaned the EGR and intake Systems, replaced all those seals and the PCV valve. Things were good for a few days and then it came back. Looked in my intake and there was a small puddle of oil. Was thinking of getting an oil catch can but I didn't yet. I decided to borrow a borescope and check out the cylinders and pistons through the spsrk plug holes. I did this when the eng was cold and just seen gunk and put it back together. I decided to look at it again the next day but this time I ran the car before I pulled the plugs. When I scoped it this time I seen what looked like water drops down the #2 cylinder. At first I thought maybe fuel injector was leaking into intake but then I realized it was on the back wall near the exhaust valves. I watched as the drip would form and then run down the cylinder. It took about a minute for the drip to form. Then I knew I needed to atleast replace the Head gasket. I read on another thread that someone had the same leak in cylinder #2 . I never notice any oil or coolant loss between oil changes so it must have just started leaking. I have now completely torn apart the engine. I have decided to change the pistons and rings IAW the TB for excesssive oil consumption hoping that fixes the oil getting into my intake through the PCV valve. Good luck with your issues and I hope your ls is fixed. If it comes back try scoping the engine after it's been running. You might have to turn the engine over to change positions of the pistons to see better in each cylinder.
     
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  19. Raytheeagle

    Raytheeagle Senior Member

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    When you do the job next time, you'll be better prepared for it:).

    Cause there will be a next time;).

    Good luck and keep us posted(y).
     
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  20. noctiluca

    noctiluca Junior Member

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    ...aaaaaand its back and worse. the codes switched to cylinders 2 and 4, so im going to replace the coils.