EGR system and cylinder misfiring

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Austin Longenecker, Sep 27, 2018.

  1. Austin Longenecker

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    I've recently taken my 2010 Prius to a new Kwik Kar to get my oil changed and my engine checked because my check engine light had come on for the first time since I purchased the vehicle last winter. I get my oil changed without a problem, but they tell me I need to replace my EGR valve and cooler, and they showed me the condition of the system and it was horribly clogged. My Prius had been comfortably surviving with the clogged EGR, no issues arose. The valve was replaced first, still no problems.

    A week later I get the cooler replaced and that's when the shaking started. My engine will shake somewhat violently when I was at a steady, low power cruise above 40 MPH (worst at 59 MPH). By violently I don't mean I feel like I'm going to lose control. I mean I feel like something's going to break and I'm going to be stranded. I've taken it back to Kwik Kar and they tell me that Cylinder 4 is misfiring. I go along with it thinking that maybe it's coincidental. They replace the sparks plugs and coil for that cylinder. My Prius is still shaking, so I take it back again and they say it's still misfiring. I've taken it back a few times with the same results: It misfires -- they change things around with the cylinders -- it still shakes -- I take it back.

    From what I can conclude, the misfiring is not coincidental. It had never started shaking until after the EGR cooler was replaced. And they cannot seem to find the real cause, or at least find a solution. The fact that they broke my windshield in the process is not reassuring. I only have 113,000 miles on the car.

    Has anyone had similar issues? Or could recommend what actions I should take?
     
  2. yeldogt

    yeldogt Active Member

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    Did they clean the intake ?

    With a clogged cooler -- you may have been getting very little exhaust gas going through it. The code was telling you that the EGR valve was not working -- or system not working. When you replaced the valve -- the valve is now working .. but the clogged cooler is still not allowing any flow of the exhaust gas into the valve. Once the cooler was replaced the exhaust was flowing .. but .... if you did not clean the intake... those now flowing gasses may not be equally going to each intake port The metal tube coming off the valve gets very coated with soot .. as does the main port of the intake ... it then branches off to four small ports to each of the intake. You make have one or more blocked -- as the valve operates it throws off the air intake to the engine .. results in misfires.

    when the system is blocked == you many not get the mis .. but the engine is running with hotter heads .. not good for head gasket.

    You may need to remove the intake and clean -- replace the PVC valve. The valve is cheap and easy to clean with the intake off.

    I recently had to clean the intake and pipe -- replace the valve and cooler
     
  3. Austin Longenecker

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    I recently moved off to start college, which meant finding a new shop. The shop had CLAIMED to have cleaned the intake. They never touched it. After a month of them proving they cannot be trusted, I was finally able to take it to a Kiwik Kar near home that I use to use and trusted, and they immediately found the problem. The intake was still clogged, so signs at an attempt to be cleaned. But we found more. The new shop that I took it to first removed a gasket and replaced it with a makeshift goo gasket that was not doing its job. They never told me about this. You hit it spot on, thank you. Maybe you should have a talk with the mechanics here, seeing as it took them a month and $2,000 to cause more problems while "looking for a solution" and you found a solution in a day and $0.

    Make sure you can trust your mechanics, Y'all. Don't go spend as much money on your car as I did just simply because your mechanic doesn't know what he or she is doing. It ain't fun.
     
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  4. bisco

    bisco cookie crumbler

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    unfortunately, with hybrids, finding a competent shop is even harder than with gassers.
     
  5. Austin Longenecker

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    This is very true, but I know that wasn't the problem in this case. I just found a poor location to take it to. These are people who wanted to take the cheap route for them and the expensive route for me. It doesn't take a genius to know that a hybrid needs real gaskets and not the makeshift substance they used or to know that if the full EGR system is clogged, simply saying the pipes were cleaned does not clean them.

    Anyway, my check engine light came back on today but the vehicle is no longer shaking. I assume that once I get that gasket and take it back to the trusted shop that that will no longer light up. I can only hope I'm done with this struggle.
     
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  6. Mendel Leisk

    Mendel Leisk Sand Pounder

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    With the EGR circuit and intake manifold, the more you can DIY the better.

    It's labour intensive, and if you work carefully, have the time, can cost you pretty much nothing, just the cost of cleaners. Both the EGR valve and cooler can be cleaned, no need to replace.

    You will need a tool set, method to safely raise and support the front end of the car, and you may need to acquire a few more esoteric tools, specifically an E8 Torx socket (for EGR studs), and possibly an E6 Torx socket (for the throttle body studs. A 12mm ratcheting box wrench is nice too, for removal of the rear bolts holding the EGR cooler to exhaust manifold. You want to have decent torque wrenches too: 3/8" and 1/4" are optimal.

    When I took the intake manifold off on ours, (albeit a lot earlier, around 70K kms) I just carefully removed all gaskets and reused. They all looked fine, like new.

    Consider an oil catch can spliced into the PCV hose between the valve and intake manifold too.

    A couple of threads worth reading right through:

    EGR & Intake Manifold Clean Results | PriusChat

    Oil Catch Can, Eliminate that knock! | PriusChat

    Also, watch @NutzAboutBolts video on egr cleaning, intake manifold cleaning, oil catch can install:

    Nutz About Bolts Prius Maintenance Videos | PriusChat

    Comment on the videos: it's not really necessary to open coolant lines for any of these procedures.

    When removing the throttle body (shown in the intake manifold cleaning video) you can leave the coolant lines attached, just separate the throttle body and shift it out of the way, say tie it with some twine.

    With the EGR cleaning, you do need to disconnect coolant lines, but if you drain a couple of quarts of coolant (at the radiator drain petcock) at the outset, it'll drop the coolant level below the EGR system, so no coolant spills when the EGR components are removed. After reassembly just pour that drained coolant back into the reservoir.
     
    #6 Mendel Leisk, Oct 1, 2018
    Last edited: Oct 1, 2018
  7. Austin Longenecker

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    I greatly appreciate your help! However, I am a college student without the knowlage, skill, time, or tools to do this myself. I hope someone with the skill will come across this thread and find that information a great help.
     
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  8. Mendel Leisk

    Mendel Leisk Sand Pounder

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    You're welcome. Watch the videos for sure: even if you don't take it on it's good to know what's involved. (y)
     
  9. Gasketblower

    Gasketblower Junior Member

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    I cleaned my EGR Valve and it got stuck again the next day! seems like its faulty motor on it, I ordered one off amazon for 250$
     
  10. wheezyglider

    wheezyglider Active Member

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    Did you maybe mean to post this in a different thread? (I know I've read some of your progress somewhere...)
     
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  11. ChapmanF

    ChapmanF Senior Member

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    How did you determine that it got stuck?
     
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  12. Gasketblower

    Gasketblower Junior Member

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    I unplugged EGR Power connection and the car runs with out any problems. When the EGR was hooked up the engine rattled and hesitated like it wanted to die
     
  13. Gasketblower

    Gasketblower Junior Member

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    Yes I did but it’s always the same people helping out so they saw it no matter where I post it lol
     
  14. mr_guy_mann

    mr_guy_mann Active Member

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    Your symptom seems more consistent with "partial clogging" of some of the EGR passages in the intake manifold. These distribute the EGR gases to each of the 4 intake runners. What will happen is that oil vapor and carbon schmutz inside the intake will build up in the small outlet ports of the passages (near the intake manifold mounting face).
    The port for cylinder 1 is furthest from the EGR valve and it usually gets the most goop built up. Eventually it will become completely restricted. So the remaining 3 cylinders are fed an amount of EGR gases meant for 4. Then cylinder 2's port get blocked.

    Now EGR gas that's enough for all 4 cylinders is fed to just 2 cylinders. Too much EGR gas will cause a misfire- which causes the the trans and damper to rattle.

    Unplugging the EGR eleminates the gas flow and thus the misfire and rattle.
    You need to remove and clean all of the parts in your EGR system- likely including the EGR cooler.

    Posted via the PriusChat mobile app.
     
    #14 mr_guy_mann, Aug 3, 2021
    Last edited: Aug 3, 2021
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  15. ChapmanF

    ChapmanF Senior Member

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    How did you get from that to thinking the valve is stuck?

    If it's stuck it can't move. If you unplug it it won't move.

    Sounds more to me like you proved it wasn't stuck, and something else about its operation was causing your symptoms.
     
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