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ICE comes on an awful lot...

Discussion in 'Gen 2 Prius Technical Discussion' started by cooljw, Nov 21, 2012.

  1. cooljw

    cooljw Member

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    I have a 2007 Gen II Prius with 60k miles on it. I used to get 50mpg easy. Nowadays more like 44mpg. Trying to figure out if something is wrong with the car.

    The only thing I have noticed is that the internal combustion engine (ICE) is on, and comes on a lot more than it used to. This definitely reduces mpg. I have two main observations:

    1.) When pressing the gas pedal, it takes a lot less of a push to get the ICE to come on. Sometimes, simply pushing the gas pedal at all triggers the ICE.

    2.) The ICE stays on for a lot longer periods than before. For example, just driving around there are times when it will stay for several seconds after I've already come to a complete stop.

    Is this a normal sign of battery degradation or could something else be wrong?
     
    #1 cooljw, Nov 21, 2012
  2. cwerdna

    cwerdna Senior Member

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    Why mileage gets worse in winter | PriusChat - some if it might be heater use

    Also, please run the test at Weird stuff happening? MPGs dropping? Test The Battery | PriusChat after the car has sat MANY hours or overnight. Please tell us the 3 values (not just 1). Don't go changing the battery first until you tell us the values...

    If you have HIDs, you can avoid unnecessary cycles on the lights by toggling between off and parking light positions.

    Weird stuff can start happening w/a low or bad 12 volt. Don't waste $ on having a dealer "test" the 12 volt (07 Prius Dead - Any Guesses? | PriusChat). If you're on you're original 12 volt, it's likely near or at end of life now.
     
    #2 cwerdna, Nov 21, 2012
  3. cooljw

    cooljw Member

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    It shouldn't be winter related issues because the drop started this Spring, and I am in SoCal and never run the heater.

    But thank you for the battery tips! I will test and report back.
     
    #3 cooljw, Nov 22, 2012
  4. nh7o

    nh7o Off grid since 1980

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    Another possibility is that the inverter system is overheating due to the well known inverter coolant pump failing. Make sure you have turbulence in the coolant reservoir tank, next to the inverter. If that loop is not working, then the computer will limit the current through the inverter as a protective measure, and require the engine to make up the difference. It's a little low in miles for that, but good to check.
     
    #4 nh7o, Nov 22, 2012
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  5. cooljw

    cooljw Member

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    Ok finished the battery test.

    1.) Shows 11.9v after not driving for 1.5 days.
    2.) Drops to 11.5v during power on test.

    I guess it's time for a new battery. Will report back my results after changing the battery.

    I saw another thread about cleaning the mass air flow sensor, I will try that too and report back.
     
    #5 cooljw, Nov 23, 2012
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  6. cooljw

    cooljw Member

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    Ok I put in a new Optima yellowtop a few days ago. The MPG and EV mode performance has definitely improved. It is now possible for me to get 50mpg again, whereas before it was difficult without severely upsetting people in the rearview mirror. Guess the new battery did the trick.

    One of these days I'll get around to cleaning the MAF too.
     
    #6 cooljw, Dec 10, 2012
    Solman636, PriusGuy32 and F8L like this.
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