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Warming up Prime in Cold weather.

Discussion in 'Gen 5 Prius Technical Discussion' started by JohnnyEmac, Feb 14, 2024.

  1. KH111

    KH111 Junior Member

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    I sat in the car yesterday, unplugged, start button pushed, pushed every defrost button I could find, and nothing. I think there is some sort of maintenance mode the dealership can use to start the engine but I was hoping for something simple.

    KH
     
  2. KH111

    KH111 Junior Member

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    It used to be common sense told you an engine that needs circulating oil and correct tolerances between dissimilar metals should have a brief warm up period before being run hard.

    Plus, I have a 45 year career of military/commercial aviation and every airplane I have ever flown required a warm up period and usually a cool down period as well. That includes recips and turbines. I don't think gas engines are fragile, I just imagine there is an increased amount of wear on a cold engine when started and immediately run at high RPM.

    I'm confident Toyota has designed their powerplant with this in mind, it's just unusual to own a car with a gas engine that can't be started.

    Without getting a scan gauge of some sort, is there a way to see the RPM of the gas engine when running?

    And, what menu do I choose to see how many miles the car has driven total with the gas engine running?

    KH
     
  3. KMO

    KMO Senior Member

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    That's because it's not winter. This is a "cold weather" thread.

    IIRC, the temperature threshold for defrost forcing the engine is 15°C, which I imagine you're above now.
     
  4. KMO

    KMO Senior Member

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    And that's what the car does. Unless you push your foot to the floor. And I thought that's the behaviour you wanted?

    If you are planning to put your foot to the floor within a minute of starting, overriding the car's reluctance to run the engine hard, then you probably do want to get running before you do that.

    Just selecting "HV" should suffice, I think. If it doesn't, push the pedal a bit.
     
  5. Zeromus

    Zeromus Member

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    Yep, modern ECUs in cars are smart, and they do their damnedest to avoid bad drivers making poor decisions in a lot of ways, this being one of them. Unlike older cars that have wires connecting the pedal to the throttle body, newer cars will retard the response in order to avoid a full throttle pushing of the engine when sensors say its not up to temp yet. On the plus side, oil is thinner now and heats up really quickly to provide proper lubrication so long as its being changed regularly and on schedule. And the engine components will warm up quickly as well thanks to modern engineering, with the appropriate tolerances to not be as easy to damage as well.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    With gen 3, just a hybrid, after start up, and for the first few blocks of warm up, the engine is just fast-idling, providing zero motivation. The propulsion down the road is accomplished purely by the electric motors. You can see this when you step on the gas, then let up: the sound of the engine doesn't budge. As previously mentioned, that may depend on how aggressive you are on the gas, I think if you try to accelerate hard then it'll call on the engine as well.
     
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  7. sylvaing

    sylvaing Active Member

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    I didn't know that. I can't try it today since it's a bit cold at 13°C. Once it warms up (at least 20°C), I'll give a try.
     
  8. KMO

    KMO Senior Member

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    Don't take it as gospel - I dimly recall it from a "New Car Features" document.

    It's kind of a bit of lore that starting the defroster "always" starts the engine, and that's what I believed, but apparently that's only because people normally only start the defroster when it's cold...

    I don't think I've ever actually tried it in warm weather since reading that myself.
     
  9. vvillovv

    vvillovv Senior Member

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    I also thought that selecting Defrost would always start the engine, until every once in a while the defroster wouldn't start the engine right away.
    Keeping in mind, most of the time there are more than one threshold for any one function programmed into the car. So if most of us hit the one most common threshold and use that as a default, that's great for the majority of us, until someone gets into a situation where one of the other minor ( to most of us ) thresholds is not met and gets confused why it doesn't work in their particular situation.

    A couple of examples regarding the engine start after switching to HV mode. If engine coolant temps are above 60 F / 15.5 C and the Prime stays under 20 mph and the Hybrid System Indicator is kept under the half mark above the ECO indicator of the gauge (like in the video below) of the ECO mode curve, the engine will stay off for a long time, relatively speaking. exceed any of those thresholds then (usually, I guess :cool: - there may be other thresholds I've not met yet ) the engine will start.




    I use the video because I pretty sure a lot of Prime owners never see that screen which is on as soon as I turn on my prime and shift into drive.
     
    #69 vvillovv, Jun 10, 2024
    Last edited: Jun 10, 2024
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  10. KH111

    KH111 Junior Member

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    I seem to have struck a nerve here. Let me try again. I literally live 100 yds away from a highway entrance, so no chance of warming the engine up in my neighborhood prior to entering a road with 70 mph traffic. I thought wouldn't it be nice to run the engine for 1 minute prior to the quick acceleration to keep up with traffic but still can't figure out how to do it. How about only charging the traction battery to 90% overnight, sitting in the driveway in D and in HV charging mode and get the engine to run to charge the battery for a minute or so? Or does the engine stop when the vehicle is stopped, darn it. Maybe just creep forward slowly but that will just be EV mode? Still don't know how to do it just sitting in the garage however especially without me in it. Really, I'm just trying to understand this marvelous piece of technology I bought without considering these things before.

    KH
     
  11. vvillovv

    vvillovv Senior Member

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    @KH111 like @KMO mentioned above, this thread is more focused on cold weather warmups. The thresholds for starting the engine when the temps are warming are much different than during cold weather situations.
    If you are thinking you've hit someones nerve in this thread, the easy way to avoid that is to start your own thread, and post as much detail as you can think of initially and you should get some decent responses.
    There cars are getting more complex with each new Generation and learning how to work around issues takes time and practice driving them.
     
    #71 vvillovv, Jun 10, 2024
    Last edited: Jun 10, 2024
  12. HacksawMark

    HacksawMark Active Member

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    While I'm not driving at 70 mph 100 yards from my home, I preset the climate controls to regular defrost and feet. I remote start the car while still plugged in. A few minutes is all it needs to melt the frost or ice on the windshield. I unplug and drive off in EV mode. In 4-5miles, I'm cruising at 55-60 mph and then I switch over to HV mode. Works well for me.

    I suggest trying the same. Once you're done accelerating and at cruising speed of 70 mph, switch over to HV.
     
  13. KMO

    KMO Senior Member

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    Even though it starts the engine for the first time due to acceleration, Auto EV/HV mode doesn't hammer the engine immediately unless you really are totally flooring it. It still attempts to do the warm-up cycle. So if you're not totally flooring it, it's functioning as intended. If you don't like the car auto-starting the engine on first demand, don't use Auto EV/HV mode, because that's what the mode does.

    I already suggested selecting HV mode immediately on start-up - doesn't that start the engine? Did you try it? I don't want to believe people come to forums seeking a complicated trick answer to "how do I start the engine?" without trying the "toggle engine mode" button, but...

    I'm assuming it should because a non-plugin Prius always starts the engine to warm up. And, as I said, if it doesn't start it spontaneously just sitting there like a non-plugin, pushing the pedal while in P and HV Mode really should make it start.

    Or you could stay in EV mode until you've joined the traffic. It's plenty fast enough.
     
    #73 KMO, Jun 11, 2024
    Last edited: Jun 11, 2024
  14. KH111

    KH111 Junior Member

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    Sorry if I came off as irritated on my previous posts, just a little frustrated trying to figure out how this engine start thing might work. Now it's like an itch I just have to scratch:). I tried HV mode and HV Charge mode sitting in the car with start button pressed, defrost buttons pressed, etc. but didn't try the accelerator just sitting there. I will keep trying various combinations of modes to come up with something.

    In the mean time we will try and accelerate in a way to let the engine management system protect the ICE on the initial start up. Thanks for the responses.

    It's my wife's car so I don't have the Toyota Connect option for remote start (without access to her phone).

    KH
     
  15. KMO

    KMO Senior Member

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    Okay, I don't understand how Charge mode could not start the engine. It should either say "charge above 80%" and refuse to enter the mode, or it should start charging.

    Did you give it a couple of seconds at least? Normal start-up delay for a Prius is about 5-10 seconds, to give you a chance to back out.
     
  16. sylvaing

    sylvaing Active Member

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    I guess they fixed an annoying "feature" with Gen4 in Gen5, which is being able to turn on defrost while plugged in. You can't with Gen4 and it's stupid. Too bad Toyota can't apply fixes like this to previous generation, which sucks.
     
  17. Louis19

    Louis19 Active Member

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    Hi sylvaing, Could it be that way, because in HacsawMark post, I note that he says remote start the car while plugged in .....
    In my 2022 Prime, a canadian model, the app does not support remote start ......so I must go into the car ...and since the car is plugged , the system will not go in ready mode preventing to leave while plugged in ....BTW the dealer told me that the app for gen 4 model in canada was........quite useless.:(
     
    #77 Louis19, Jun 11, 2024
    Last edited: Jun 11, 2024
  18. KH111

    KH111 Junior Member

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    Honestly not sure if the traction battery was already charged to 100% or if I did not wait long enough for it to start. I will try it again tomorrow if I get the chance.

    KH
     
  19. Isaac Zachary

    Isaac Zachary Senior Member

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    1,500W or 2,000W circulating block heater.

    Or just throw in a 1,500W space heater and close the door on the cord.

    I've tried both on other cars with good results (just not at the same time).
     
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  20. KH111

    KH111 Junior Member

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    The simplest solution is usually the right answer. Just found out the engine will start in Park, start button depressed (ready , HV mode and the accelerator pedal slightly depressed. It then continues to run for a few minutes completing it's warm up cycle before shutting down. You can get out of the car, with or without the key for that warm up cycle.

    Thanks for all of the suggestions.

    KH