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Unplug EGR Valve

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Paladain55, Oct 20, 2021.

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  1. Paladain55

    Paladain55 Active Member

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    I consider it permanently fixed now so that's why. No more cleaning egr. I know there are some rule sticklers here who prefer to have the system fully functioning as intended but it still takes a couple hours to clean that crap. Now I never have to ever again. Lol
    I did clean the manifold though and it got it fully functioning, but then unplugged it again. At least if I sell it it won't have a cel for the next owner. So there ya go that's my findings with the egr system.
     
    #21 Paladain55, Jan 8, 2022
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  2. Caleb Stoll

    Caleb Stoll New Member

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    Are you saying you can run the car with egr unplugged and you don’t get the cel symbol coming on? Could you explain the process in detail?
     
    #22 Caleb Stoll, Feb 9, 2022
  3. StarCaller

    StarCaller Senior Member

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    people just ignore it /
     
    #23 StarCaller, Feb 9, 2022
  4. Paladain55

    Paladain55 Active Member

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    Yes you get a cel code. I just ignore it. Check my scan Guage on occasion to make sure it's not any other codes. We aren't in limp mode and the car runs smooth still. I think this mod makes the gen 3 prius more reliable like the gen 2 prius.
     
    #24 Paladain55, Feb 12, 2022
  5. ChapmanF

    ChapmanF Senior Member

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    It also retards the ignition timing.
     
    #25 ChapmanF, Feb 12, 2022
  6. mjoo

    mjoo Senior Member

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    I don't want a retarded Prius.

    moto g power ?
     
    #26 mjoo, Feb 12, 2022
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  7. Paladain55

    Paladain55 Active Member

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    Update: We have hit 200k. I've figured out oil consumption is mostly just tied to RPMs. Oil consumption was not affected by swapping viscosity either. 0w-40 consumed like 0w-20. I found that the car consumes oil above 3000 RPMs usually on long highway trips and its very hill/mountain-ey here. Keeping RPMs below 3000 RPM car consumes a quart of 0w-20 every 6500 miles. EGR is unplugged. Still getting around 54 mpg average for now. So we don't have a bad head gasket but we do have bad piston rings. I replaced the spark plugs back around 120k but I will probably do them again here soon and attempt to do a leak-down test as well. Past that the car still drives very well. Somewhat respectable. Oh and I still have p0401. I haven't noticed any limp mode effects or extra CEL codes.
     
    #27 Paladain55, Mar 3, 2022
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  8. Paladain55

    Paladain55 Active Member

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    *above code is p0403 not p0401
     
    #28 Paladain55, Nov 14, 2022
  9. ChapmanF

    ChapmanF Senior Member

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    Driving around with the timing constantly retarded is a kind of a "limp mode effect", just maybe not severe enough that you notice it.
     
    #29 ChapmanF, Nov 14, 2022
  10. rjparker

    rjparker Tu Humilde Sirviente

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    It would seem this whole discussion is purely academic if the cooler was 100% plugged anyway. Unless the real issue is a leaky egr valve at low rpms which causes a bad idle or misfire and perhaps gets mechanically sealed off by the owner. We know the egr valve should be closed at startup and low engine power.
     
    #30 rjparker, Nov 14, 2022
  11. Paladain55

    Paladain55 Active Member

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    The car does run a different map by the way so you are correct. Its like a fail safe running mode. The biggest difference i see is the amount of load the engine uses at each rpm is different than running with EGR connected.
     
    #31 Paladain55, Nov 14, 2022
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  12. mattf1a

    mattf1a New Member

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    I have a question about Disabling the EGR valve: If my engine gives me rough shuddering accelerations when starting from a stop, but it runs smooth at driving speed, and if I disable the EGR by unplugging the harness and then the engine runs smoothly in all conditions, does that mean that there is nothing wrong with my head gasket? Forgot to state that I have a 2014 Prius V with 162000 miles and have never had a problem with it until the rough acceleration thing started a couple months ago.
     
    #32 mattf1a, Aug 2, 2024 at 10:35 PM
  13. rjparker

    rjparker Tu Humilde Sirviente

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    A better test is to block the egr tube from the valve to the intake. If the egr is not working or leaking it will allow exhaust into the intake regardless of the electrical. Also aftermarket egr valves are known to stick open.


    Car Care Nut video with egr block tube test


    Rough shuddering is more commonly a leaking head gasket on these engines but blocking the egr can remove egr from the list. Don’t waste your money on plugs, coils or injectors when the issue goes away quickly as you describe.
     
    #33 rjparker, Aug 3, 2024 at 11:48 AM
    Last edited: Aug 3, 2024 at 11:57 AM
  14. mattf1a

    mattf1a New Member

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    Thanks for the reply and the video link. I had watched that before but wasnt sure about running with a spatula in place. So if I block the EGR with a spatula and the problem goes away we can conclude that it is NOT a head gasket?
    One other detail here is that if I open the cap on the coolant reservoir in the morning after it sits all night I have a good puff of pressure blowing out the exit tube..
     
    #34 mattf1a, Aug 3, 2024 at 11:59 AM
  15. rjparker

    rjparker Tu Humilde Sirviente

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    Yes - after a couple of weeks. We have seen people change plugs and the symptoms go away for a short time. Others loosen up the reservoir cap and eliminate symptoms for weeks. Meanwhile an underlying hg gets worse in many cases and that’s not good if it costs an engine.

    A quality dual view borescope when cold with pumped up coolant pressure is the most definitive test from a hg fail standpoint on this engine.

    Car Care Nut HG Borescope at 7:40
     
    #35 rjparker, Aug 3, 2024 at 3:41 PM
    Last edited: Aug 3, 2024 at 4:39 PM
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