SUDDEN drop of about 10MPG

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Zardoz, Jul 11, 2019.

  1. lech auto air conditionin

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    Try this on your next hot day start up .
    1: when you get to your car roll all four windows down even open the doors for a few minutes because it’s easier to cool down 108° outside air then it is 150+ degree inside cabin air.
    2: have the air conditioning turned on to fresh air not recycle Air. because recycled air would be a lot hotter in the cabin then pulling in outside hundred + degree air. Once you start to feel cold air coming out of the dash while you are still parked . Now drive for one or two blocks with the windows down. Roll up your windows.. there’s one thing you must realize when your car has been sitting in baking it’s not only the air that is 150° plus in temperature it’s all the plastic and glass the weight the mass of all the material in the vehicle needs to be cooled down first before the air conditioning can start achieving its maximum lowest temperature. Because as fast as the air conditioning can pump out cold air the cold air is absorbing the heat out of all the interior of the cars material to try to cool that down to not just the air .
    3: now that you have been driving once you have noticed that the interior cabin air is at a lower temperature then the outside ambient temperature you can now switch the fresh air to recycle mode because now it will be easier to cool off the cooler interior cabin air then trying to cool the outside ambient hot air .
    But this is only if your air conditioning refrigerant is 100% properly charged a Prius has very low capacity of refrigerant and only two or 3 ounces being low on hot days will make a big difference of your dash out put air temperature. On top of that if you refrigerate level is a few ounces low the compressor will be working overdrive winding it self to death trying to achieve to cool the cabin but it cannot because being low on refrigerant so this will draw a shit load of amps from the HP battery depleting it causing the engine to come on more often lowering gas mileage greatly.
     
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  2. jerrymildred

    jerrymildred Senior Member

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    That's almost exactly my practice. Well said. (y)
     
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  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Funny that it’s still a manual list of chores in the most automated cars on earth.
     
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  4. alanclarkeau

    alanclarkeau Senior Member

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    I don't have (or want) a SUNROOF - but I'm told that it's a good option to open it to let heat out too.
     
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  5. jerrymildred

    jerrymildred Senior Member

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    Yeah, I have no desire for one either. Just another opportunity for leaks. But it would vent hot air in a hurry.
     
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  6. jerrymildred

    jerrymildred Senior Member

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    Ditto. They have the computing power, the controls, and the sensors. All they need is more ambitious (or thoughtful) programmers.
     
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  7. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Something extra I like to do, though gotta say we only rarely use the air:

    Start the air conditioning in "auto". On a hot day the fan will promptly race. Raise the cabin temperature setting until the fan speed drops, close to median speed. This might mean raising the temp to around 38~30C. This will still be cooling though.

    In a few minutes, as the fan speed drops a notch or two, cabin temps stablilize, lower the cabin temp, a degree or two. Never so much that the fan races. Repeat this process as the cabin cools. I find settling around cabin temp 24C is usually the sweet-spot.
     
  8. The Professor

    The Professor Active Member

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    My experience is that it'll race until the temperature drops considerably anyway. No need to set the temperature higher. Just set it to the temperature you want it to be inside the cabin. If you want the fan faster for longer set it to Auto Fast. If you want it slower, set it to Auto Eco. If you want it somewhere in the middle, set it to Auto. It does a good job on its own.
     
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  9. jerrymildred

    jerrymildred Senior Member

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    That still uses more energy, though, because you're still cooling super-hot air rather than just hot air from outside. The A/C drops the temperature of the incoming air a fixed amount. The hotter the intake air, the hotter the discharge air.
     
  10. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Does Auto switch it to recirc? Can't recall. Roger* the outside air is usually preferable. And the mention up the page to try to exhaust the hot cabin air with windows rolled that, copy that*.

    * Listening to:

    Apollo 11 in Real Time
     
  11. The Professor

    The Professor Active Member

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    That's a configurable setting in Carista. But mine blasts outside air for a while, then gradually slows the fan, then engages recirculation. That may take a few minutes to 10 minutes maybe. That's in UK weather.
     
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  12. alanclarkeau

    alanclarkeau Senior Member

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    Last thing you want in a dodgy location is to start your PRIUS and it opens the windows!!!

    My last workplace was like that (I ended up paying for secure parking) - but at least FORD allows you to program the unlock to ONLY unlock the Driver's Door.

    TOYOTA - nope, too much trouble, even on their technological showpiece. And the FORD would auto lock all doors at some stage - I think when it started moving, or maybe put into gear.
     
  13. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    As with so many other automated features, they’d have to fork it somewhere. One press for secure cool-down, tap twice for maximum cool-down (windows open) really wouldn’t be much harder.
     
  14. alanclarkeau

    alanclarkeau Senior Member

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    I just double press UNLOCK - and the windows come down. You have to keep the button down to get them all the way down - unlike FORD, VW etc which are one-touch for a full down, 3rd press if you only want them part-way, which is rare.
     
  15. lech auto air conditionin

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    That’s because they did not have me design the heat exchangers and Refrigerant choice and mode of operation.
     
  16. The Professor

    The Professor Active Member

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    Some of these are also options available in the settings or Carista (at least they are here in the UK).

    My car originally had it set to unlock just the driver's door on single press of unlock button, and all doors on second press. I set it to unlock all doors, as I have a whole family to get into it more times than not. If I recall correctly, this is just in the car settings somewhere, either the ones on the MFD or the other ones on the Infotainment system.

    I used Carista to set it so that holding the unlock button drops all the windows as well as unlocking, and holding lock puts them back up (I know the latter isn't available in all locales).
     
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  17. alanclarkeau

    alanclarkeau Senior Member

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    Yes, I can do the open and close of windows - I think it's USA which won't close them again. But - why TOYOTA doesn't do it as standard, nobody knows. But the Manual lists it as an option. VW and FORD - you don't have to ask - it's just there.

    With the unlock only Driver's Door - the Manual doesn't list it as an option which was quite a surprise. So I went back to the salesman (who had been the PRIUS Mechanic before he had an arm injury) - he chased it up and came to a dead end. So they all unlock now - I jump in and hit LOCK.

    I'll make certain to ask before I buy next time.
     
  18. The Professor

    The Professor Active Member

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    It's because the fob buttons can be accidentally pressed while the fobs are in pockets. I've certainly done this many times. I turn this feature on during hotter months, and back off again for the rest.

    More than once I've heard my car alarm going off, only to discover the windows are all wide open (air currents and flying insects trigger the ultrasonic sensors), or come back to the car in the rain to find the window control switches drenched with water.
     
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  19. alanclarkeau

    alanclarkeau Senior Member

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    Odd - here, I have to unlock it once, then press it again, and HOLD it while they drop - it doesn't start for a second or 2. Locking is the reverse. So if it happened to me, it would only be open a very small amount (unless I held it down).

    PS - please send us some of your rain :D
     
  20. The Professor

    The Professor Active Member

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    Yeah it's just a long press here. Also, if you do long press to open the windows (or short press), and nobody opens a door for 30 seconds, it'll lock the doors automatically.

    You can have the rain! Never stops here. It's meant to be the Summer but it's rained more days than not.
     
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