EGR carbon build up

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by 2ewes4me, Mar 30, 2020.

  1. 2ewes4me

    2ewes4me Junior Member

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    Our 2011 was making some loud clanking noise, especially upon start and low speeds. O'Reillys scanner said code PO401, misfire and EGR. We brought it to the Toyota dealership and they diagnosed random cylinder misfire due to severely cartooned up intake manifold causing EGR valve to stick open. The dealership is closed due to coronavirus, so we brought it to a trusted local mechanic. He cleaned the intake and cooler/pipe, and replaced the EGR valve; said everything was pretty cartooned up! With 238,000 miles he said we could save $ by seeing if we could get another 100,000+ by not replacing the intake manifold.
    We drove off, happy that the repair was half the estimate from Toyota.
    However... we noticed another rattle at low speeds, and the check engine light came on about 20 miles away from the local mechanic's. Called him and he said to drive it another day or two and see if it doesn't burn off and run smoother. He said spark plugs may need replacement (they have 114,000 miles on last replacement).
    Advise please-
     
  2. Raytheeagle

    Raytheeagle Senior Member

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    Did they just do the valve or the egr cooler as well :whistle:?

    I'd also get the code confirmed through reading the code;).

    It's a shame the plugs weren't done while all the other stuff was removed:cool:.

    Good luck and keep us posted(y).
     
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  3. 2ewes4me

    2ewes4me Junior Member

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    The receipt says : Diagnostic scanner,
    additive SF16- Carbon cleaner, replace EGR valve, clean cooler & pipe.

    We'd told him the plugs were done not that long ago when he'd asked, but when we actually checked the maintenance log, the plugs were replaced at 124,000 miles. That was 114,000 ago....
     
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  4. Grit

    Grit Senior Member

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    I used to wake up Saturday mornings to watch looney tunes. I was cartooned up myself :D
     
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  5. Mendel Leisk

    Mendel Leisk Senior Member

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    SF16 seems to Sea Foam, according to Google anyway.
     
  6. 2ewes4me

    2ewes4me Junior Member

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    30 miles later and as the car pulls into the garage, it is rattling loudly. Taking off from a standstill, until I hit about 9 mph, it shakes like I'm driving on speed rumble strips. But when the gas pedal is depressed at moderate and high speeds, no noise at all. I went through a drive through, and while electric is powering the car, it is still silent, but when gas engine kicks in, it rattles moderately. check engine sometimes flashes, but mostly solid. No other warning lights.
    Do you think there's any chance this will eventually 'burn off" an run smoother?
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Very likely the mechanic didn't do a thorough and complete job. Are you able to DIY? I think you need to see for yourself, what's done, and not done.
     
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  8. Raytheeagle

    Raytheeagle Senior Member

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    Are the dash lights still on:whistle:?

    I'd still look to have them read ;).

    The codes will lead you to the next step :).

    Good luck and keep us posted (y).
     
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  9. 2ewes4me

    2ewes4me Junior Member

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    Mechanic has worked on our cars for years, so no reason to think he wasn't thorough, but suppose it's possible. It was something he said he hadn't done much of prior
    The only dash light on is the Check Engine.
     
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  10. Raytheeagle

    Raytheeagle Senior Member

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    So what's the reason (code) the check engine light is on for:whistle:?

    That'll tell you where to look:).

    There are many reasons for the check engine light to illuminate;).

    Get that code and let us know(y).
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Too, with 238K miles, and no EGR cleaning up till now, odds are about even that the head gasket has already let go. You didn't mention dropping engine coolant in reservoir, it's steady?
     
  12. 2ewes4me

    2ewes4me Junior Member

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    Got into town to get the codes today. (previously PO401) Today they were new codes:
    PO300, PO303, PO304, P2119A (Random engine misfire, Cylinder 3 misfire, Cylinder 4 misfire, throttle actuator(?)

    The engine coolant is steady.

    The local mechanic that replaced the EGR and cleaned the cooler/pipe suggests changing the spark plugs and coil boots. Before we spend another $200 to get that done, we'd like to hear
     
  13. 2ewes4me

    2ewes4me Junior Member

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    we'd like to hear what your experiences are. A throttle Actuator just sounds expensive!!
     
  14. pjksr02

    pjksr02 Active Member

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    Unfortunately, the coils and plugs aren't often a problem with these symptoms. Your mechanic (or you) could swap coils 3&4 over to 1&2, and see if the problem moves.

    At this point, consider a leak-down test and or cylinder scoping, due to the likelihood of a failed head gasket. Coolant leaking into cylinders can cause misfiring.

    Have you ever noticed white exhaust smoke?
     
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