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HV powering car after cold start

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by amellb, Dec 19, 2011.

  1. amellb

    amellb New Member

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    This is something I have noticed the last 3 months. I have had the car 2 years.

    When I first start it and it is completely cold, it will only run like EV mode (HV battery powering the car) even though the gas engine is merrily running and it is not in EV. We live part way down a small hill, so now I often discharge the HV battery to a point low enough to trigger the recharge function which keeps the gas engine running forever. It does this morning or afternoon, if it has been sitting a few hours and is completely cooled off. It did it in Sept. at 65F and it does it now at 35F.

    It only does it for about the first 0.25 mi, then it is warmed up enough and goes back to normal where the gas engine recharges the HV battery and powers the car forward.

    Our street is pretty quiet, and I have been able to flip between indicator screens. I can see the HV battery powering the wheels, while the gas engine does not recharge it. The gas engine just runs but does not send power anywhere, either to power the car or recharge the HV battery.

    I took it to a dealer and they checked the computer for error codes, but there were none. They are going to drive it around tomorrow morning with the checking device attached, to see if anything comes up.

    It is not a major issue, just a minor annoyance. But it does mess up the gas mileage in warm weather because the gas engine runs longer than would be needed for warmup, in order to recharge the HV battery which was drained by powering the car. And it is definitely a distinct change that happened 3 months ago, and continues every day.
     
    #1 amellb, Dec 19, 2011
  2. cwerdna

    cwerdna Senior Member

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    It sounds like the ICE could be running to provide requested cabin heat. See bottom of http://priuschat.com/forums/gen-iii...mileage-gets-worse-in-winter.html#post1411488.

    Also, since I doubt you have any instrumentation to monitor ICE/coolant temperature, the ICE may not be sufficiently warmed up. Please read http://priuschat.com/forums/gen-iii...-discussion/76501-gen3-warming-up-stages.html.

    If you want the ICE to warmup quicker and loose less heat, you should block the grille in colder weather.
     
    #2 cwerdna, Dec 19, 2011
  3. cproaudio

    cproaudio Speedlock Overrider

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    I start driving as soon as I hit the power button. I've gotten my Prius to 50mph on EV while the engine warms up at a slight down hill. At that point, the engine sends power to the wheel and the instant MPG drops to 10mpg. To me it's not so much of an annoyance because I have the Enginer kit charging the HV pack.
     
    #3 cproaudio, Dec 19, 2011
  4. amellb

    amellb New Member

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    It seems like it is stuck in S1a for several minutes, not just 50 seconds. So if I start out with only 2 or 3 bars on the HV, I can deplete them as I go up our hill at 12mph.
    It does it in warm weather (September) or cold weather (now). It does it mornings, or afternoons. This didn't happen last winter during our deep freeze, or the first winter which was more normal. It didn't happen until September, and since then it happens every day.
    I don't turn on the cabin heat for at least 10 min. after starting.
     
    #4 amellb, Dec 19, 2011
  5. Kore971

    Kore971 PEDD-CESC

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    It sound like normal operation to me.., mine behaves that way especially with temps below 65 degrees F..., especially if you deplete the battery to 2-3 bars the night before, because when it is in s1a it powers the car mostly by HV battery power which is why it drains so quickly when you drive it on a cold startup.., i usually wait about 50 seconds when driving on a cold startup before i pass the "center line" on the 'HSI'..., however in colder temps (40 degrees) it will sometimes take longer than 50 seconds before it acts "normal"...
     
    #5 Kore971, Dec 20, 2011
  6. adamace1

    adamace1 Senior Member

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    Do you really want a cold ICE having to rev up alot doing a cold start or wait till it's warm.

    I'm not sure but i thought they did this to prevent wear to the ICE. Cold starts are very hard on all gas cars.
     
    #6 adamace1, Dec 20, 2011
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    My understanding is this is normal, ie: When you're driving right after startup, virtually all propulsion is from the electrics. The engine is fast idling, but idle speed stays more-or-less steady. I think unless you really step on the gas.
     
    #7 Mendel Leisk, Dec 20, 2011
  8. cwerdna

    cwerdna Senior Member

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    So you're not using auto on the HVAC and the fan isn't on w/a temp above LO?
     
    #8 cwerdna, Dec 20, 2011
  9. bisco

    bisco cookie crumbler

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    is this new on the genIII? i don't notice it on the II.
     
    #9 bisco, Dec 20, 2011
  10. cwerdna

    cwerdna Senior Member

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    Which part are you asking about?
     
    #10 cwerdna, Dec 20, 2011
  11. adamace1

    adamace1 Senior Member

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    I thought more about it, The car is warming up the catalytic converter before it has to rev the ICE up. This reduces emmisions and wear.
     
    #11 adamace1, Dec 21, 2011
  12. amellb

    amellb New Member

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    Thanks everyone for the input.
    The dealer drove it around with the code checker attached and couldn't find anything.
    I don't turn the fan or heat on at all for 10 min. (It helps living in the south where this is easy). It is set off, not auto or any fan speed.
    It used to get out of s1a while I was in our driveway, which takes me about a min. It is a distinct difference that changed in September, spending a longer time in s1a so now it takes the first 0.25 mile to get to the next stage.
    I can adjust my driving to compensate, it is just a minor annoyance, and I wondered if anyone else had reported it.
    Thanks again.
     
    #12 amellb, Dec 23, 2011
  13. ken1784

    ken1784 SuperMID designer

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    If you drive average 15mph, it takes only one minute for the 0.25 mile.

    Ken@Japan
     
    #13 ken1784, Dec 24, 2011
    1 person likes this.
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