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Violent engine shaking at startup. Miss fire codes all cylinders

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by rjp123, Apr 4, 2019.

  1. rjp123

    rjp123 Member

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    I have a Prius Gen 3 with 206K, and am suffering from extreme engine shake at ICE startup.

    The event last about 5-10 seconds. A loud mechanical knocking noise and visible shaking of the engine, then perfectly smooth. It never returns again until next startup.

    It has done this off and on for the past 100K miles or so, but it was only a few time a year and impossible to reproduce for the dealer so I never paid it much mind. A few days ago, however, it started doing this every time the engine starts as long as it has been off for more than about 5 minutes. Even if it is just sitting in the driveway idling. Hot/cold makes no difference. So now it is very reproducible.

    I currently have missfire codes on all cylinders: 0300, 0301, 0302, 0303. Permanent, Stored, and pending. So the shaking is due to missfire. But why is it missfiring?

    I did some reading and it seems many owners are experiencing engine shake like this but I don't see a clear resolution identified, or even a cause. I saw a few cures mentioned including: intake manifold replacement, EGR system cleanout, PCV valve and more. Has Toyota posted any update on this issue?

    If there are any good threads I should read please direct me. I want to learn how to fix this. I hope to do the work myself.

    As far as maintenance, I has the EGR replaced under warranty when the TSB came out about rought starting a few years ago but it made no difference. I replaced the plugs, coolants, ATF, and PCV at 116K miles. I plan to do the plugs again tomorrow but have little hope it will make a difference.

    No significant oil consumption. However, I did notice the ICE coolant is a few inches low in the tank. However, I haven't checked this is since I replaced it 4 years ago I'm ashamed to say, so I have no idea if it is a recent drop. I guess that's a testimony to just how remarkably reliable this car has been! No need to even open the hood basically for 206K miles other than oil changes.

    Thanks for any help
     
  2. Pluggo

    Pluggo Senior Member

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    I had that same horrible engine shake happen exactly one time after I accidentally plugged in a code reader while the car was still powered on. In my case it lit up several warning lights, told me the hybrid system failed and to park the car. It threw a bunch of codes about bad communications: this not communicating with that and the other not receiving information from some such-and-such a system. Don't rule out a software problem.
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    They may have just replaced the EGR valve, leaving the (clogged) EGR cooler and EGR passages in the intake manifold untouched. And that was 100K back.

    I would start by checking the condition of the EGR pipe, watch @NutzAboutBolts video (see last link). This will give you some idea of the condtion of the rest of the system.

    This is something you pretty much HAVE to educate yourself on: Toyota and the dealerships have completely dropped the ball.

    EGR & Intake Manifold Clean Results | PriusChat

    Oil Catch Can, Eliminate that knock! | PriusChat

    Nutz About Bolts Prius Maintenance Videos | PriusChat
     
  4. rjp123

    rjp123 Member

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    Thanks for these links! I will definitely watch that video about cleaning the EGR system.

    I was considering taking it into Toyota dealership for diagnosis now that it is highly reproducible and happens every time the ICE starts after 5 minutes off, and there are 4 missfire codes set. It will be hard for them to say it's "normal" in this condition anyway ;)
     
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  5. The Critic

    The Critic Resident Critic

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    Are you losing any coolant? Check the coolant level in your reservoir.
     
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  6. MikeNinMass

    MikeNinMass Junior Member

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    Oooch... not just a Gen 3, but a 2010, with over 150K, and low coolant.

    Sorry to mention it, but it sounds like a head gasket. Look up threads on head gaskets.

    If you have a slightly leaking head gasket, of which high mileage Gen 3's are susceptible (and 2010/early-2011's in particular), coolant droplets can slowly drip into the cylinder while the engine is resting for a while. At cold start, the liquid can mess with the cylinder ignition until it makes its way out as steam, then everything is fine until enough liquid builds up again.

    I think someone mentioned releasing pressure from the coolant system at engine shutdown (be careful) could reduce dripping into the cylinder(s), which could reduce symptoms. That might be a test, but is not a cure. Someone noted on changing the head gasket that the leakage was enough to cause a bent connecting rod. Get this checked right away before a whole engine tear-down or replacement will be needed.

    By the way, when I went to look for a replacement for my 2010, I had a shop look at two other 2010's from different used car lots, and both had visible dampness in the head gasket area, but were bone dry above and below. That's how I found out about the head gasket issue.
     
    #6 MikeNinMass, Apr 4, 2019
    Last edited: Apr 4, 2019
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Still, DIY is likely the best route. You may be able to get them to do this under warranty, but don't assume they'll do it right, and completely. They will likely not interested in cleaning components (which are perfectly usuable, once unclogged and cleaned), would much rather just swap parts, and they're all very expensive.

    The drill:

    1. Clean the EGR circuit, completely, from the connection at the exhaust to the capillaries in the intake manifold, one per port.

    2. Clean the intake manifold and throttle body, MAP sensor (use MAF sensor cleaner, to be safe).

    3. Install Oil Catch Can on hose between PCV valve and intake manifold.
     
  8. rjp123

    rjp123 Member

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    Yes, as I mentioned, the coolant reservoir is down a few inches but I don't know how long it took to get that low. Don't think I've checked it in 4 years since I replaced the coolant in 2015. I marked the level today for reference.

    I suspect you are right that it is a head gasket. Hard to believe a partially clogged EGR circuit or oil and crud in the intake or TB could cause this. If it were once in a while, maybe, but this knocking is every time the engine starts after just 5 minutes off. Even while driving or waiting in traffic.

    Thanks for the head gasket suggestion. Do you know of a good link describing this issue?

    Is there a way to determine if the head gasket is leaking other than taking the head off and looking at it?
     
  9. rjp123

    rjp123 Member

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    Yes. It is a few inches lower than it was when I changed it 4 years ago. Not sure if it dropped recently.
    Thanks for head gasket link.
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Put masking tape on the reservoir, and with the car level put a mark at the current coolant level, on the masking tape, then monitor.

    FWIW, over the first maybe four years of ownership, both the inverter and engine reservoirs on ours dropped to the low lines. I got a gallon of the proper coolant, topped both up, and they haven't budged since.

    If coolant is leaking due to a failing head gasket, I think you'll see very definite drop, over a week or two.
     
  11. The Critic

    The Critic Resident Critic

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    Sure thing, let me know if I can help. I just did the job last month so it is fairly fresh in my mind.

    I would top off the coolant and pressure test the system. After allowing it to sit for a while, check for coolant intrusion into each of the cylinders.

    I do not know if an engine with 206k is worth repairing, especially if you have to pay someone. There are a lot of issues that could arise once you take it apart. Depending on how much coolant has been consumed you may have bottom-end damage. You may also find pitting on the block. Are you currently experiencing any oil consumption? If so, then it is definitely a reason to not repair the current engine.

    The flat-rate labor time for a head gasket repair on these cars is 17.2 hours. Obviously this time contemplates engine removal, but the job can be done in the car without removing the engine. Due to the way that the auto repair industry is set-up, industry norms dictate for jobs to be charged at flat rate labor times and not by actual time taken. So, most shops will be charging the 17.2 hours if not more. I am not sure what the labor rates are in your area, but in my area it is > $120/hr for independents and >$160/hr for dealers. Assuming the engine is repairable, you will also need an overhaul gasket kit, spark plugs, thermostat, water pump, oil, oil filter and coolant which can easily reach $1K if purchased from the dealer. Plus machine shop costs ($200+) if you elect to have the cylinder head resurfaced and new valve stem seals installed.

    If the head gasket is really your problem and you are unable to fix it yourself, in all honesty, I would start looking for another car.
     

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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    These guys don't have the best table manners, but I get the sense they run through it what, 8 hours? Less:



    Good to watch if you're contemplating DIY too. Their's a few things you would NOT want to do their way, their leisurely/funky application of timing chain cover Form-In-Place gasket for one.
     
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  13. rjp123

    rjp123 Member

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    Thanks. I have already read your entire thread just now. Very helpful!

    I would do the work myself. I have replaced head gaskets on other cars before, but no experience with Prius.

    Basically, I just want to be 100% sure it *needs* a head gasket before tearing into it. Maybe the coolant level will drop in the next couple days to confirm loss. Also, I may take a look down the plug holes this weekend with a bore scope and see if I see coolant. That should confirm it for sure.

    One thing that seems a little strange to me is that I have recent (pending) missfire codes on all 4 cylinders. I would think that if a head gasket develops a leak it would not immediately start leaking into all cylinders, just one or two where the breach is. So I'm holding out hope (slim hope) that it may be something else common to all 4 cylinders.

    It was running fine up until a few days ago.
     
  14. rjp123

    rjp123 Member

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    Excellent! Thanks for all this info.
     
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  15. rjp123

    rjp123 Member

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    Wow, I watched the head replacement video and it looks easier than I imagined. Feeling motivated now!

    Normally I would buy a service manual but thanks to all the great pages posted above I don' think I'll need one. Thanks!
     
  16. MikeNinMass

    MikeNinMass Junior Member

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    The other thread to follow is the 3rd sticky, started by danlatu, at the top of the threads in this section, plus all the ones that show up at the bottom of this page as "Similar Threads"
     
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  17. Raidin

    Raidin Active Member

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    The violent shudder on cold start ups is a known defect on a few Prius engines. There is a TSB for that that calls for either a new intake manifold or a software update to reduce the likelihood of it happening.

    If you get the shudders all the time, I agree you may be looking at a head gasket failure. This is how it happened to me. I got the shudders all the time instead of the rare occasion, and then it moved to even while I'm driving. My mechanic was able to find oil and coolant in both the cylinders and throttle body if that helps.

    Best of luck whatever your specific situation ends up being.
     
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  18. rjp123

    rjp123 Member

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    If the problem really is the head gasket, should I be able to see coolant on top of the pistons if I look in the spark plug holes after it's been sitting for a while? It seems like that should be the case.
     
  19. The Critic

    The Critic Resident Critic

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    Yes.
     
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  20. The Critic

    The Critic Resident Critic

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    Try a short-term subscription from alldatadiy.com. It pulls info from the factory service manual.
     
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