Death Rattle... clean manifold & EGR, new plugs, no change

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Nor'easter, Oct 13, 2021.

  1. Nor'easter

    Nor'easter Member

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    2010, 121K miles, daughter's daily driver. Last night she pulls in the driveway and the engine is making an awful death rattle. No codes.

    Today I 1) swapped the EGR cooler out for a clean one. The "old" EGR cooler was not blocked, I could see daylight through it. 2) cleaned the EGR valve, pipe, intake manifold. Nothing was blocked or significantly obstructed. 3) installed new plugs. Originals look just like you'd want them to look at 121k miles. 4) Changed PCV. Old PCV perfect, rattles as it should. Car burns no oil to speak of, I never have to add between oil changes. All synthetic all the time, never more than 7500 miles on an OCI since new.

    I have been monitoring the EGR with techstream. Last time I verified the EGR circuit was open was less than 2k miles ago and indeed, it looked fine. Sadly, today, my old techstream laptop won't boot. Of all the dumb luck....

    Coolant level is right on full. No white smoke. No oil consumption. Minimal oil found in intake manifold.

    After all that, it starts up, purrs like a kitten, then after a while the rattles start in earnest. What in the hell?

    It sounds like exhaust hammering on the chassis (not heat shields) with busted engine mounts. It is freaking LOUD while driving at low speed/low RPM/windows down. High RPM no issue. In maintenance mode, the engine ran quiet and smooth for ~ ten minutes. Turning the AC on full blast (this has been implicated before) and after a few minutes the rattles start. Turn AC off, rattle persist. Turn engine off, on again, rattles gone. Rattles are accompanied by vibration you can feel in passenger compartment.

    Tomorrow I take a closer look at exhaust & engine mounts, but it doesn't feel like this is the problem. The rattles are deeply mechanical and they come on like a light switch.

    Ideas?
     
  2. rjparker

    rjparker Senior Member

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    I would block the egr tube temporarily and see if the rattle goes away. The egr should be closed at low rpms or it can cause misfires. The misfires can cause a loss of sync with the transaxle causing the noise.
     
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  3. ChapmanF

    ChapmanF Senior Member

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    When the traction battery doesn't need charge, the engine idles. Runs around 1000 rpm not doing any work to speak of.

    When the traction battery needs charge, MG1 produces it, and that puts mechanical load on the engine. Still runs around the same rpm, but now it is doing real work. Goes back to idling when the battery is back up to a target charge. Those changes do come on and off very much like a light switch.

    Running the A/C will use energy from the traction battery faster, so it reaches the point sooner where the engine load increases to charge it.

    Anything that lets the engine run smoothly at no load, but with misfiring at slightly higher load, will have the effects you describe.
     
  4. Nor'easter

    Nor'easter Member

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    Good points twice, thanks both.

    I'm not convinced it's misfiring.

    It feels & behaves more like there's an uneven load on the engine. One would think that if MG1 were only generating power on 2 of three phases that we'd get codes. That's what this problem feels like.
     
  5. JC91006

    JC91006 Senior Member

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    You can force charge the HV battery to full and test. Force charge the HV BATTERY to full by putting the car into drive, holding the brake down and flooring the accelerator.

    Once the HV battery is fully charged, put it in inspection mode and let it idle. See at what point on the battery State of Charge meter reaches when the loud knocking starts.

    You can run the test again with the AC blasting and see if the knocking comes on at the same battery SOC (low).

    I would suspect there isn't enough fuel getting to the car. So my guess would be a bad fuel pump or injectors. Or maybe you don't have enough gas in the car
     
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  6. ChapmanF

    ChapmanF Senior Member

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    This is well-traveled ground here in Prius land.

    You might take a look at this article, with special attention to "Why the knock" on page 4, before giving your final answer what you think it feels like.
     
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  7. Nor'easter

    Nor'easter Member

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    More data: Cold start, engine runs smooth at low/no load. With engine warm, car stopped (engine off), traction battery at 60%+... shift to drive with brakes on hard, gas pedal depressed, engine starts, runs smooth, HSI indicates battery charging. Any gas pedal setting (brakes on, car stationary), runs smooth. On the road, runs like crap at light load. Runs fine at high load (when HSI indicates "power"). Runs great at full throttle.
     
    #7 Nor'easter, Oct 13, 2021
    Last edited: Oct 13, 2021
  8. rjparker

    rjparker Senior Member

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    Read my post again.
     
  9. jzchen

    jzchen Senior Member

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    To those of us who may not know, ie me, can you please share how one might block the EGR tube?

    REVVL V+ 5G ?
     
  10. xliderider

    xliderider Senior Member

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    There's a YouTube video where a small putty knife is slipped between the EGR valve and tube to block off the flow to rule out an EGR valve that is stuck open or partially open.

    Posted via the PriusChat mobile app.
     
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  11. Nor'easter

    Nor'easter Member

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    Thanks twice I guess. A link to more info of some sort would be great.

    Given the history of blocked EGR systems causing e.g. blown head gaskets, perhaps you can understand why I didn't run out and try this first thing? Furthermore, there's no obvious way to do so.
     
  12. burebista

    burebista Member

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    Here you go.
     
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  13. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Did you get the small EGR passages, one at each intake port?
     
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  14. jzchen

    jzchen Senior Member

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    Thank you for the direct link!

    Be advised there seems to be a revised EGR valve:
    04004-58137 (kit with gaskets except)
    25685-37010 (EGR Cooler Gasket #1)

    Intake manifold:

    17120-37091
    I just noticed this wording and interpreting:
    "If current part number is 17120-37090, do NOT replace". I interpret this as meaning what you should see emblazoned on port #4, -090 when shopping for the part on the used market....

    I suspect the updated manifold to be 17120-37090, and the -91 is the kit. (So many half truths out there).....

    References:. T-SB-0103-12 Rev2, and T-SB-0027-16. (I keep learning as I go, didn't know the Rev# was important before).

    If you are OC like me just pay Toyota $20 and look up what the latest is: techinfo.toyota.com .


    REVVL V+ 5G ?
     
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  15. rjparker

    rjparker Senior Member

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    Actually there is little evidence or even support outside of Priuschat for the clogged egr head gasket thesis. Hearing it repeated over and over again from a single source and then believing it is a problem.

    An egr is designed to be closed at low speeds and at wide open throttle. If it is not, misfires are common. This is the typical egr issue across most internal combustion engines that mainstream mechanics understand. Since you had been in the egr yesterday, the piping should have been pretty fresh.
     
    #15 rjparker, Oct 14, 2021
    Last edited: Oct 14, 2021
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  16. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I've got a recollection, trying to corral all the 3rd gen intake manifold iterations (part no's); think I threw in the towel around 5... Just clean what you got works for me.
    Why are my ears burning...
     
  17. rjparker

    rjparker Senior Member

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    I was talking about a certain media network. Since you are in Canada you don't have to choose sides. Especially if you keep the oil changed, the egr spotless and the car garaged.
     
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  18. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Hell, I can't even find excuses to drive it. Was supposed to do an airport run, but they've got someone else now.
     
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  19. jzchen

    jzchen Senior Member

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    @rjparker Well I would not personally know as I'm not a mechanic by trade, but if it sounds like the engine is tearing itself apart I assume it actually is, (or what sounded like an animal being burnt inside and jumping around in my case)...

    I even accidentally forgot to add oil once in my last oil change. Engine ran perfect for the one minute or so it took me to realize why the red oil (genie) lamp was lit, and turned it off. Should have sent a video to Mobil that their Annual Protection was that good....

    Since I believe @ChapmanF found them on NHTSA somewhere, I'll try to post the important pages...

    REVVL V+ 5G ?
     

    Attached Files:

    #19 jzchen, Oct 14, 2021
    Last edited: Oct 14, 2021
  20. rjparker

    rjparker Senior Member

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    Down in Texas we fire up the car to pick up the mail. Seriously. My mailbox is a mile away with a 200 foot elevation drop. Lightning storms are interesting from our vantage point. This was two weeks ago.

    DA9C1B09-125F-4FD3-ABEE-78B5FFBFB089.jpeg
     
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