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[Help] Prius revving while driving or braking 2010, 195k miles

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by mindfk, Jul 6, 2018.

  1. mindfk

    mindfk Junior Member

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    Yesterday my Prius started acting in a very unusual way while driving home from work, at first during low speed driving it would engage the engine in weird situations as if it was charging a battery when it is depleted, that would cause a jerk and the engine would rev up to keep up with the load. Few miles down the road, on an interstate it then turned into a full blown uncontrolled revving while driving, braking or in neutral while coasting - like it wanted to keep charging the battery even if the battery was full full - as per the display.

    I just got a check engine light but it's the standard lean condition p0171...no exactly what i expected.

    Also, when i'm stuck in traffic it would dip rpms's to the point where everything sounds like a cold start knock and then it either corrects itself or the engine dies like it normally does when EV takes over.

    See video below from some highway over-revving action:
    https://photos.app.goo.gl/eLELaZSoL6Jnoq6R8

    Any ideas?
     
  2. JC91006

    JC91006 Senior Member

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    Try cleaning your throttle body and MAF SENSOR. While you're in there, check the air filter
     
  3. mindfk

    mindfk Junior Member

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    Air filter is good, I replaced it within last 10k miles; I will do MAF and throttle first and report back.
     
  4. JC91006

    JC91006 Senior Member

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    after cleaning the 2, you should disconnect your 12v negative for a minute to reset the car. Or else it might run really rough

    If this doesn't cure it, then you might have to do an EGR circuit cleaning afterwards.....which is a good 4 to 5 hours of work
     
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  5. The Critic

    The Critic Resident Critic

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    Get access to a scan tool and check your fuel trims. See if your lean condition is most prevalent at idle or at 2500 rpm. My guess is that at your mileage, the fuel pump is probably the culprit.


    iPhone ? Pro
     
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  6. Raytheeagle

    Raytheeagle Senior Member

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    4 to 5 hours with the proper assistance ;).

    First time doing the job (without a spare egr cooler) will be a solid 8-9 hours.

    Good luck to te OP and keep us posted (y).
     
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  7. tankyuong

    tankyuong Senior Member

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    check your 12v battery
     
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  8. JC91006

    JC91006 Senior Member

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    I'm not looking forward to doing mine lol
     
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  9. Raytheeagle

    Raytheeagle Senior Member

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    I’ll be in your neck of the woods the week after thanksgiving :).

    That Friday we usually do a half day in Disneyland, so always looking for a way to get away;).

    A week there is more than enough :sick:.
     
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  10. JC91006

    JC91006 Senior Member

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    We'll go out for a drink, forget fixing cars on vacation
     
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  11. Raytheeagle

    Raytheeagle Senior Member

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    Sounds like a plan :).

    I’d like to see your setup;).

    If it comes with beverages, I’m good with that too(y).
     
    #11 Raytheeagle, Jul 6, 2018
    Last edited: Jul 7, 2018
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  12. 4est

    4est Active Member

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    Check oil level
    If it is low, you are in big trouble
     
  13. mindfk

    mindfk Junior Member

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    I did a catch can mod a while ago; after unbolting the intake i discovered that the nipple came off the manifold; you can imagine how surprised I was to see this. I cleaned the throttle and MAF anyways - took it for a spin and it does not surge/stutter/knock at low rpm which is good. Revving while driving/coasting did not go away yet - that's probably because I did not disconnect the battery to reset the ECU and it's still correcting for a gaping 1/4in hole that I had from catch can hose adapter. I will reset asap.

    After around 150k miles my my Prius became a thirsty SOB; it burns around a quart every 4.5k miles, I change oil every 8-9k using 0w20. I plan to keep adding oil until this thing blows up which is probably within the next 50k miles... or max 2 years... which is good enough for me.
     
  14. Raytheeagle

    Raytheeagle Senior Member

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    A quart every 4.5 k miles isn’t bad at all;).

    Ever consider clubbing up in oil viscosity?

    At 195 k miles, your egr circuit is plugged with carbon deposits :(.

    I’d look for a window of time to clean it before the head gasket gives way;).

    Good luck and keep us posted (y).
     
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