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Engine keeps running after battery is charged

Discussion in 'Gen 2 Prius Main Forum' started by jk4322004, Jan 28, 2009.

  1. jk4322004

    jk4322004 New Member

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    My engine keeps running after the battery is charged, the engine comes on while driving when it should not come on, and my mileage is way down. There have been some cold days since this started but there have been warm days too. Anyone know what is going on? Thanks for any replies.
     
  2. efusco

    efusco Moderator Emeritus
    Staff Member

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    What car do you really have? AFAIk there's no such thing as an '03 #5 Touring.

    For the 2G Prius, if the SOC gets high, which it tends to do when you're running the heat in the winter b/c the ICE runs harder to warm up and spills the excess energy into the battery. When the battery SOC gets high (green level) the car will cycle the ICE on and off in an effort to get the SOC down toward it's happy level of about 60% SOC. (top blue bar).

    Also, if you're running defrost the ICE will rarely shut off. And make sure you're not driving in B-mode...that'll kill your mileage and force the ICE to run continuously.
     
  3. qbee42

    qbee42 My other car is a boat

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    How do you know that your engine should not be running. As a quick exercise, list all of the conditions that cause the engine in a Prius to run or stop.

    Okay, do you have your list? I thought not. The control algorithms on the Prius are very complex. Many of us have been studying them for years and still don't know all of the details.

    There are three primary reasons for the engine to run: 1) Provide power to move the car, 2) Provide power to charge the battery, and 3) Provide heat for the engine, catalytic converter, and cabin.

    Any of these reasons, and several more, can cause the engine to run. Most of the time the engine should run when the car is moving. Driving on electric is your least efficient mode, since the electric power you are using had to come from the gas engine, get converted to electricity, get converted to chemical energy, get converted back to electricity, and finally get converted back into mechanical energy. Every one of these conversion steps wastes energy.

    Most likely your loss of mileage is due to cold weather. Check your tire pressures too if you haven't done so recently.

    Tom
     
  4. Rokeby

    Rokeby Member

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    jk4322004,

    Welcome to PriusChat from a fellow Merilander.

    qbee42 and efusco know whereof they speak.
    (Hint: check out their join dates and post counts in their avatars. :eek:)

    Methinks you are somewhat confused... No problem, education is the answer.

    There is an awful lot to learn about how the Prius operates and what you can
    do to get the best MPGs, especially in cold weather. Try this as a start --
    and be sure to read the cited threads at the end of the piece too:

    http://priuschat.com/forums/knowled...perating-mode-availability-reference-aid.html
     
  5. daniel

    daniel Cat Lovers Against the Bomb

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    Assuming you have a Gen II (2004 - 2009) Prius, my first guess is that the heater or defroster is on, causing the ICE to stay on. Once the car is well warmed up, that should not be an issue.

    If you really have a Gen I (2001 - 2003) I think that model shut off the ICE far less often than does the Gen II.

    If you drive a Gen II long enough for everything to get good and warm, and the ICE still refuses to shut off when the battery is full and the power demand is low, then it might need to be looked at by a tech. On the other hand, if you drive hard on the accelerator, that, too, will keep the ICE running.

    So much we don't know about your situation...
     
  6. auricchio

    auricchio Member

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    And once you hit 42mph the ICE cannot ever shut off, because it is protecting the motors from overspeed.
     
  7. Kyankov

    Kyankov Junior Member

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    Similar issue with my prius 2007.

    Any ideas guys? Was overfilled in Toyota. Then had to clean oil from throttle body myself, changed the 12v battery and still this issue and lower mpg. I was driving for 15 minutes before taking the video. Vent in the back is not heard, so battery is not overheating.
     
    #7 Kyankov, Jun 2, 2017
    Last edited: Jun 2, 2017
    Sohail@100 and ArturPriusGen2 like this.
  8. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    You have added to a thread last posted on 8 years ago about a Gen 1 Prius. It is possible those posters are no longer active or never had a Gen2 Prius like yours.

    I would start an all new thread describing all you know about YOUR car, and your symptoms.
     
  9. Sohail@100

    Sohail@100 New Member

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    How can u solve this issue
     
  10. Sohail@100

    Sohail@100 New Member

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    How can u solve this my prius is same issue afyer cleaning the throttle myself