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EGR cleaning, now mpg drop

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Daniel Richard, Aug 27, 2019.

  1. Daniel Richard

    Daniel Richard Member

    Joined:
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    Minnesota
    Vehicle:
    2010 Prius
    Model:
    I
    I cleaned my EGR, EGR cooler, and intake manifold. The system was completely blocked. Now my mpg’s have dropped. Any idea why? Do I need to reset the computer?
     
    #1 Daniel Richard, Aug 27, 2019
  2. Raytheeagle

    Raytheeagle Senior Member

    Joined:
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    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Welcome to Prius Chat (y).

    Some questions:
    • How many miles on your Prius?
    • Did you perform any other maintenance at the same time as the egr circuit cleanse?
    • Any dash lights?
    • How many miles have you put on since the cleanse?
    • What type of driving have you done since the cleanse?
    • Any change in weather in your neck of the woods that might have caused AC usage?
    Good luck and keep us posted (y).
     
    #2 Raytheeagle, Aug 27, 2019
  3. Daniel Richard

    Daniel Richard Member

    Joined:
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    Location:
    Minnesota
    Vehicle:
    2010 Prius
    Model:
    I
    No other work don’t to the car.
    No CEL.
    About 100 miles.
    I only drive interstate at 70 mph.
    No change in weather.

    I am thinking I am going to disconnect the 12v battery to reset the computer.

    Any other thoughts?
     
    #3 Daniel Richard, Aug 27, 2019
    Mendel Leisk likes this.
  4. schmuber

    schmuber Member

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    Location:
    Georgia
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    2010 Prius
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    N/A
    You've introduced new variables into equation, ECU noticed it and recalibrating. It'll pass.
     
    #4 schmuber, Aug 28, 2019
    Threej and TheeWood like this.
  5. mjoo

    mjoo Senior Member

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    Location:
    Michigan
    Vehicle:
    2010 Prius
    Model:
    III
    How old is your 12V battery?

    When you performed your maintenance did you put a charger on the 12V? Any chance the interior lights were used? A dying 12V battery will also drop fuel economy.
     
    #5 mjoo, Aug 29, 2019
    Raytheeagle likes this.
  6. Daniel Richard

    Daniel Richard Member

    Joined:
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    Location:
    Minnesota
    Vehicle:
    2010 Prius
    Model:
    I
    Nothing was left on.

    It’s been about 300 miles since I cleaned it and the mileage seems to be back where it was. I am assuming the ecu had to recalibrate.
     
    #6 Daniel Richard, Aug 29, 2019
    Greenteapri and Raytheeagle like this.
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