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Still P0401 after cleaning egr !! should we drive it?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ozmatt, Mar 27, 2021.

  1. ChapmanF

    ChapmanF Senior Member

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    I don't either, but what I'm using 'nib' for is the metal bit (and 'ski jump' for the plastic one).

    The 'nib' seems to have a taper. It's wider at the bottom, but not so wide at its top where it digs through the ski jump.
     
  2. ozmatt

    ozmatt Active Member

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    No worries, we can make it up as we go lol :)

    They are all like it though I guees, not just mine..

    The scrape in my ski is miniscule compared to even the top of nib, the two do not match up forensically ..hehe

    This plastic seems to be a very hard compound, I need some donor material to build it up a bit down there for an experiment, although I don't think the repair will last more than a few drives it would at least tell me if it's the problem..

    Be nice if someone else that had a rotor fail could verify condition of their ski lol

    Posted via the PriusChat mobile app.
     
  3. ChapmanF

    ChapmanF Senior Member

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    It's sure funny about perception ... I'm looking at those same photos and thinking "gosh. look how well those match up!"

    Does it change anything to observe that the whole diameter of that metal disc is rather smaller than the inside diameter of the rotor?
     
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  4. ozmatt

    ozmatt Active Member

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    wonder are we looking at the same thing here, the "score" looks about half as wide as nib maybe i am wrong, i will try to measure it later

    will try to build it up with some ABS when i get time later

    egr rotor.jpeg
     
  5. ChapmanF

    ChapmanF Senior Member

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    To my tired eyeballs ... green about the size of the metal disc on the stem, yellow the nib on the metal disc ....

    egr_rotor.jpg

    If the rotor is a thermoplastic, the "I don't want to do this again" fix might be a small square of aluminum sheet or the like, heated, sunk into the plastic at the end of the ramp, little epoxy behind it binding it to the ramp ....
     
    #85 ChapmanF, Apr 2, 2021
    Last edited: Apr 2, 2021
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  6. ozmatt

    ozmatt Active Member

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    Yeah okay when I take into account the taper of nib and edges around the scrape have been hot and flared up, I have to think you are right, thanks for the shake up.. :)

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  7. Rebound

    Rebound Senior Member

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    Did you clean the intake manifold?
    Specifically, there are small passages which can only be cleaned with a pipe cleaner. Did you make sure these are clear?

    These diagnostic codes only guide the mechanic in diagnosing fault. Like when you get an O2 sensor code, many people replace the O2 sensor, but the O2 sensor was never bad to begin with.
     
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  8. ozmatt

    ozmatt Active Member

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    just noticed this! .. good idea, i don't see how that could hurt providing its weaker than the nib so it does not start to wear the nib, what's the worse that can happen if it falls out and floats around a day or two until P0401 makes me aware ..

    Still don't hold much hope for this being a long lasting repair more than an experiment as we still have not identified the original cause! i am (without evidence) blaming excessive movement in the thread allowing nib to somehow run above the ski, unless it was temperature related issue as the day i got P0401 was nearly 40c mid summer and i was on a hill climb with fully loaded car
     
  9. ozmatt

    ozmatt Active Member

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    absolutely mate, whole system is spotless from the tiny intake ports to the exhaust manifold
     
  10. ChapmanF

    ChapmanF Senior Member

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    That's not necessarily farfetched.

    The time I repaired a friend's washing machine timer, it was just a clockwork motor rotating some plastic discs, the discs had notches, and there were electric switches operated by levers that dropped into the notches. It was a really old washing machine, and some of the switch contacts were oxidized and higher resistance, so they were making extra heat, and their levers got hot, and made themselves new notches in the timing discs, in between the ones that were supposed to be there. Of course the new notches weren't very deep, so they kind of kept the switches half-made, which further deteriorated the contacts, made even more heat, and made bigger new notches.

    If that rotor is a thermoplastic material, and the day was really hot to begin with, and the car was loaded heavily, and you were flogging it uphill, and that metal stem was bathed in a flow of exhaust gas ....

    Hmm. One thing, when the nib is against the stop, the valve is closed, so at least the stem isn't bathed in a flow of exhaust gas right then. And when the valve opens, the stem probably gets hotter, but the nib isn't touching the stop then.

    If you're running at pretty high load but not all-out, the valve is probably pretty far open. It's getting hot from a strong flow of exhaust, but it is nowhere near the stop.

    But if you go from there to really full throttle, I think the ECM may close the valve then to get you really maximum power. Then the valve stem is probably pretty hot, and pressed back against the stop.
     
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  11. ozmatt

    ozmatt Active Member

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    Chapman, very reasonable explanation and I hope you are right, I also changed it from 10w30 semi to 5w30 full synth a week earlier which is only rated to (from memory) 36c or 38c and this day got over 40c so perhaps the oil started to crap out and fry via the egr, I won't panic and rush the 5w30 out of it tomorrow as we are about to come into winter but next summer it's getting 10w40 and it will be staying at that viscosity from then on..

    I fix washing machines most days :) mechanical timers suck! .. direct drive machine & digital controller for the win :) but yeah I know exactly what you are saying

    Haven't done anything about the valve today as I want to make the best effort I can at repairing it, my hands are sore! It's a beautiful 33c day easter eve and right now all I'm really interested in tbh is this bottle of Beam in my cupboard lol

    meanwhile we drive around in our noble steed NHW20R

    Posted via the PriusChat mobile app.
     
    #91 ozmatt, Apr 2, 2021
    Last edited: Apr 2, 2021
  12. ozmatt

    ozmatt Active Member

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    Decided against adding any foreign materials to this rotor as I will replace it if this experiment works! .. thinking about what to use for filler material, i keep looking over at the intake manifold thinking it's probably a similar plastic :) what you think?

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  13. ChapmanF

    ChapmanF Senior Member

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    Haven't a clue. A lot of the plastic parts have a material code molded in somewhere, but I don't remember seeing one on the rotor.
     
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  14. ozmatt

    ozmatt Active Member

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  15. Mendel Leisk

    Mendel Leisk Senior Member

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    You guys maybe onto something, how the EGR valve fails, or at least one of the ways. Needs some sort of sum up, when the dust settles, and/or pinning?
     
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  16. ozmatt

    ozmatt Active Member

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    Hey Mendel, yeah hopefully we have figured at least one of the ways this thing can fail, it would be really nice if someone out there who replaced their rotor/spring could look at their old one and compare the plastic ski bit to mine ..

    Discovered the tip on the soldering iron that i use for plastic melts is not long enough to make it all the way down into the rotor where i need to manipulate it, the eczema on my hands has gone full bloom (which really frustrates me no end) and its easter sunday! really don't feel like piddling around making a longer tip for the iron right now.. clean clothes today and continue with this little experiment tomorrow

    you know i will follow up right to the end and perhaps even longer lol :)
     
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  17. sLick415

    sLick415 Member

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    Interesting thread. That could certainly explain the persistent code even after cleaning the circuit and ports. I don't suppose Toyota sells just the magnet huh?

    I just came across this article while trying to see if anyone sells the magnet on its own. He replaced the stator, magnet and spring and the code finally cleared. My guess is, his magnet probably had the same stripped stopper you have.

    Do keep us posted!
     
  18. ozmatt

    ozmatt Active Member

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    Hi Slick :)

    Nah, they don't sell it separately unfortunately .. i wish!

    Yea, i noticed that article myself and wondered the same thing

    .. Really hoping to get back to it later today, had to give my hands a rest i made the mistake of taking myself off my eczema meds which ended badly lol but getting better now! :) ..

    Been racking my brain to figure out the best way to get a repair out of this magnet, i was planning on using a soldering iron but now Im thinking of getting an old butter knife, slimming up the end of it and putting an 90 degree bend on it so i can heat it up and push the outer edge of the ski ramp in a little to give me a bit more meat up top to play with, then use the folded portion of the HOT bent knife to stamp the excess plastic DOWN into the crack as filler and smooth it over ..

    Not expecting it to be a lasting repair but would like to buy myself some time, if i get a couple trips or just one good test result from techstream, i will be very happy!

    If anyone has a magnet and spring they would be kind enough to sell me (with postage to AU) please send me a message

    PS. i was looking at 4th gen egr valves purely to rob the magnet and spring but one ebay member tells me they are different, can anyone confirm?

    Cheers all :) stay tuned for update later today or maybe tomorrow
     
  19. ChapmanF

    ChapmanF Senior Member

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    Different part number anyway. I think there was also a part number change that took place during Gen 3. Replacement required untaping the wire harness to make the connector reach, and reflashing the ECU.

    I have no insider information on what the changes were.
     
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  20. ozmatt

    ozmatt Active Member

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    Hey ChapmanF, sorry i haven't got a result yet.

    Yep, i was wondering if its just different number but effectively the same parts