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Idle Check

Discussion in 'Gen 2 Prius Fuel Economy' started by The Tramp, May 9, 2008.

  1. The Tramp

    The Tramp Italian Prius Expert

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    Hi guys,

    I need help in answering this one. :D

    I have someone questioning why such a technologically advanced car should have such a strange behaviour:

    As we all know the car needs to do an idle check while standing still to pass from S3 to S4. Right?

    The question is: why do an idle check if the car is not supposed to idle at all? :rolleyes:
     
  2. ken1784

    ken1784 SuperMID designer

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    Hi from Japan,
    We've never heard the reason of the idling check from Toyota officially, but unofficial words from a Toyota engineer was the idling condition has to be checked periodically because of contamination in the throttle body.

    The original NHW10 Prius does not have the idling check program, then it need routine throttle body cleaning for stable idling rpm, say once a year. The NHW11 and later model do have the idle check, and they don't need the throttle body cleaning so often, maybe once every 5 years.

    Ken@Japan
     
  3. Ichiro

    Ichiro Member

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    What is the definition of 's3' and 's4'?
     
  4. JimboK

    JimboK One owner, low mileage

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    They are warmup stages for the Prius. See this for a thorough discussion.
     
  5. cwa

    cwa Member

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    Hi Ken

    Sorry about asking this at a later stage.

    I have Prius 2007 (JDM) model. I have had the same situation where most of the time it want properly jump from S3 to S4 (as for the idle check). In my daily commute, I rarely get a chance to stop (turn off) the vehicle.

    My question is - what are the other ways to jump from S3 to S4 (Will it happen if I stop and park the vehicle for 5-10 sec, or costing without the accelerator for say 20 S?)

    Regards

    CWA
     
  6. ken1784

    ken1784 SuperMID designer

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    On the following two cases, you can suspend the idling check ceremony during driving.

    1. Accelerate above 62km/h, then you can coast without the idling check.
    2. If you have enough battery charge level and driving below 60km/h, press the EV button on coasting.
    These procedure are just for suspending the idling check.
    Prius needs the idling check at later time (read no magic to jump S3 to S4 during driving).

    Ken@Japan
     
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  7. cwa

    cwa Member

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    Thank you KEN. Therefore for optimum FE, we have to stop the car for 5 Sec (to go to S3 to S4).

    Regards

    CWA
     
  8. cwa

    cwa Member

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    Is there a way to know we are in S3 without any special external meters (like ScanGuage/Supermid)? If we know the S3 status, we can stop/turn off/5-10Sec/Start process should put us on S4.

    Appreciate your valuable inputs.

    Regards

    CWA
     
  9. ken1784

    ken1784 SuperMID designer

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    During idling check coasting, the engine runs using small volume of gasoline.
    Then, the energy monitor screen shows approx 75km/L instantaneous fuel consumption number.

    Ken@Japan
     
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  10. uart

    uart Senior Member

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    Hi Ken. With my Prius the coasting "threshold" seems to be 56 km/h. If I start a glide from 56 km/h or above then the engine cuts out, whereas if I start from 55 km/h or less the engine continues to idle (unless it's already in stage 4).

    Also the EV button here doesn't work above 44 km/h, so there's an annoying "dead zone" between 44 km/h and 55 km/hr where there's no avoiding the engine idling unless you're in stage 4.
     
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  11. uart

    uart Senior Member

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    Hi cwa. The easiest way to tell that the car is ready to move to into stage 4 is by the very fact that the engine continues to run if you start a glide below 56 km/h.

    While the car is warming up I'll typically test it by just backing off the go pedal for a few seconds when the speed is 55 km/h or less. If the instantaneous fuel consumption goes to zero (zero L/100km) then I know that I'm still in stage 2 (assuming here that we're not still in stage 1 or already in stage 4). If on the other hand the engine keeps running then I'll see that the fuel consumption is non zero and then I'll know it's reached stage 3 and is therefore ready for the idle check.

    BTW. Do you use MPG or L/100km there in Sri Lanka?
     
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  12. uart

    uart Senior Member

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  13. cwa

    cwa Member

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    Thank you uart.

    Here in Sri Lanka we use km/l. Best was 36 km/l (No A/C, only me). Current average is 24 km/l (With A/C, bump to bump traffic, 4 passengers).
     
  14. uart

    uart Senior Member

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    That's really good cwa. I'm also averaging about 24 km/L (4.2L per 100km) here. :)

    BTW. You might be interested in the little converter program I wrote if you want to compare results with others here using different units. It's simple and free and I've uploaded it to the file library here. :)

    See : http://priuschat.com/forums/file-library/69451-simple-fuel-consumption-converter-calculator.html
     
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  15. cwa

    cwa Member

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    Thank you. It is a little beauty.
     
  16. ken1784

    ken1784 SuperMID designer

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    We are talking about cwa's JP Gen2 Prius.
    It seems your Australia models is same as UK's.

    Ken@Japan
     
  17. uart

    uart Senior Member

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    Ok I get it, so the "JDM" model is Japanese model. So ken do you also use km/L or do you use L/100km ?
     
  18. ken1784

    ken1784 SuperMID designer

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    JDM stands for Japanese Domestic Market.
    We only use km/L unit.

    Ken@Japan
     
  19. uart

    uart Senior Member

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    Ok I've got it. :thumb:

    Thanks Ken
     
  20. Marbe

    Marbe New Member

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    Has anyone found a fix for this idle check?
    I am getting really frustrated with this stage 3 idle check every single day
    When I drive to work I have a 5 minute downhill at 30 mph and my engine is constantly on and it actualy burns fuel not a lot but it does
    I usually stop for the damn idle to do it's thing but not every day I can or have time