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MPG Drop after EGR Clear

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by d4vit, Sep 13, 2023.

  1. d4vit

    d4vit Junior Member

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    Hello,
    i have this kind of problem on my Toyota Prius Gen 3 (2013) and i hope someone from this forum can help me because i've tried everything.

    My MPG got dropped by half when i had 40 mpg stable i did EGR/Throttle/Intake clear and my MPG dropped to 20-25 after that i have no errors no faults

    Heres things which i've done:
    • I've changed spark plugs
    • i've change air filter
    • i've checked battery's in service all are good
    • i've checked Upstream(Oxygen Sensor 1) and downstream (Oxygen Sensor 2 after cat.) live data on scan tool all is smooth and fine , perfect air/fuel ratio
    • i've changed engine oil
    • i've checked all wheels pressures

    but still no big change i only feel some little change when i start to drive without A/C but before EGR clear i was using A/C same as after EGR Clear but i had good MPG
     
    #1 d4vit, Sep 13, 2023
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  2. Magic Mark

    Magic Mark New Member

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    I'm wondering if a gasket is leaking on one of the components you cleaned? I'm trying to think of a hose that might not have been missed or something that wouldn't throw a code.
     
    #2 Magic Mark, Sep 13, 2023
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  3. JC91006

    JC91006 Senior Member

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    That is a drastic drop in MPG. What type of plugs did you put in? Ones you bought from the dealer and not ebay right?
     
    #3 JC91006, Sep 14, 2023
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  4. d4vit

    d4vit Junior Member

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    Yes but as i said i did spark changes after mpg drop after egr service before all worked like a clock
     
    #4 d4vit, Sep 14, 2023
  5. d4vit

    d4vit Junior Member

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    I also thinked that egr got dead but i should get at least fault code on diagnostic but i dont get it and tbh that is the only one thing which i didnt checked but i think i would get some changes or noice or error code but no all is clean
     
    #5 d4vit, Sep 14, 2023
  6. d4vit

    d4vit Junior Member

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    so no one can help me on so big forum? :(
     
    #6 d4vit, Sep 24, 2023
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Where’s “GE”? Are you in the United States of America? Or? Are there Toyota Dealerships nearby?
     
    #7 Mendel Leisk, Sep 24, 2023
  8. d4vit

    d4vit Junior Member

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    i'ts country Georgia we dont have official Dealership of toyota here
     
    #8 d4vit, Sep 24, 2023
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  9. JC91006

    JC91006 Senior Member

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    I would suspect your brakes are somehow involved in the lowered MPG. It could be possible your brakes slide pins are stuck (possibly due to lack of lubrication) or your calipers are no releasing the brake pads.

    Weak batteries or engine issues would not account for that drastic of mpg drop
     
    #9 JC91006, Sep 24, 2023
  10. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    What’s the miles (or kilometres)?
     
    #10 Mendel Leisk, Sep 24, 2023
  11. Mr. F

    Mr. F Active Member

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    Is the 20-25 MPG reading over a short drive or over a longer period of time? Any misfires at all?
     
    #11 Mr. F, Sep 24, 2023
  12. d4vit

    d4vit Junior Member

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    no missfires at all, cant go more than 40 MPG i have range in between 35-40 MPG with long drive
    measured compressions in cylinders and i have 12.5 Bar in each im thinking it can be Spark plugs, but i receive 0 obd code
     
    #12 d4vit, Apr 23, 2024
  13. TheLastMojojomo

    TheLastMojojomo Active Member

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    @d4vit Did you Disconnect your 12v Battery before doing the EGR Cleaning?
     
    #13 TheLastMojojomo, May 8, 2024
  14. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Again, what’s the miles?
     
    #14 Mendel Leisk, May 8, 2024
  15. d4vit

    d4vit Junior Member

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    I'm back with the same problem so far. I am once again fighting to fix the low MPG issue. I'm not sure if it's EGR-related yet, but here’s what I’ve done so far:

    • Tried changing the ECU
    • Replaced spark plugs with OEM Denso
    • Measured compression (I have 11.5 on each cylinder)
    • Changed injectors
    • Tested the 12V system: it's holding 12V when the car is off and 14V when the car is on
    • Replaced the MAF sensor
    • No DTC available at all car is super clean on OBD2 diagnostics
     
    #15 d4vit, Sep 24, 2024
  16. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    What's the miles?
     
    #16 Mendel Leisk, Sep 24, 2024
  17. d4vit

    d4vit Junior Member

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    #17 d4vit, Sep 24, 2024
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  18. d4vit

    d4vit Junior Member

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    0g of oil leak
    All piston compressions are good
    Sevice being done every 6-8 months
     
    #18 d4vit, Sep 24, 2024
  19. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    How recent was the EGR cleaning? Anything specific prompt you to do it?

    With 170K miles, and presumably EGR only recently cleaned, I'd suspect head gasket failure
     
    #19 Mendel Leisk, Sep 24, 2024
  20. MAX2

    MAX2 Member

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    #20 MAX2, Sep 25, 2024
    Last edited: Sep 25, 2024
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