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Engine knocking at start up... Did not complete warmup cycle the previous night

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Roger T, Dec 30, 2014.

  1. Roger T

    Roger T Member

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    As title.

    Sometimes I have to park my car two blocks away in the afternoon, and later in the evening i need to park my car back to the spots in front of my apartment.

    EV mode won't be enough to last the two blocks, even at 7 bars. Or sometimes the car won't let me turn on EV mode, even at 7 bars (battery too cold).

    So the engine must run if i want to park my car back near my apartment. But the two block distance will not suffice to completely warm up the engine

    So the next morning... (20~ Fahrenheit)

    My car knocks for a few seconds the next morning the car starts up...

    What is the definition of completing the warm up cycle? 120F? My car will turn off the engine after coolant temp reaches 120F (ECO mode).
     
    #1 Roger T, Dec 30, 2014
    Last edited: Dec 30, 2014
  2. JC91006

    JC91006 Senior Member

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    I find my car turns itself off after about 1 minute. But I'm in CA, it's not that cold here. Next time when you are in your parking spot, just wait til the engine turns off before you shut down.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Was it knocking then, the next morning?
     
  4. bisco

    bisco cookie crumbler

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    make sure the heat is off, then it will complete as quickly as possible.
     
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  5. The Electric Me

    The Electric Me Go Speed Go!

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    I don't necessarily see a problem here.

    You seem to be equating not being able to fully warm up the engine, in a short duration drive as being "the reason" your vehicle is then knocking on start up on a cold morning.

    Really, what options do you have? Either wait until the engine reaches temperature every time you use it, or not. If I'm moving from parking spot to parking spot, personally I'm just turning the vehicle off as quickly as possible and living with any possible knocking with the next start up.

    Unless the knocking is so horrible or of such a long duration that you suspect damage is being done, I'd just ignore the whole thing. I'd also suspect the "cold engine" knocking symptom will dissipate in Spring and Summer.

    It's winter, it's cold, and your engine is knocking for a few seconds on start up. I wouldn't sweat it.
     
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  6. Roger T

    Roger T Member

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    Yes, knocks for a few second the next morning. I read some old related threads. It seems like a common issue of knocking when car did not completely warm up the previous trip and the car is parked in the cold overnight.

    I hope to avoid the knocking! Loud and sounds harmful. I will wait until the engine shuts off itself to at least warm up the car a little more the next time in the short trip i park my car back to my apartment.
     
  7. Roger T

    Roger T Member

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    Thanks for your response. So true. My car knocked for like 2 seconds at start up.

    I don't think it is a big problem either. Just hope to bring it up here to discuss about it.
     
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  8. bisco

    bisco cookie crumbler

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    i believe it's unburnt fuel in the intake manifold. a redesign was supposed to help, but apparently not. still seeing problems. it's not a big deal, but i wouldn't want it happening everyday if it were my car.
     
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  9. fuzzy1

    fuzzy1 Senior Member

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    More likely not the battery, but the engine coolant is too cold, below 68 degrees F.
     
  10. Sporin

    Sporin Prius Noob

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  11. Roger T

    Roger T Member

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  12. fuzzy1

    fuzzy1 Senior Member

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  13. bisco

    bisco cookie crumbler

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    yeah, unfortunately.
     
  14. Roger T

    Roger T Member

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    It does not happen often... i only saw it happened once this winter.

    And in the previous night, i drive it for 30 sec then turn off the car when the engine is on... I think that's why it would happen.
     
    #14 Roger T, Dec 30, 2014
    Last edited: Dec 30, 2014
  15. Roger T

    Roger T Member

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    Thanks for your comment. Looked up Ken@Japan's thread:

    S0:
    • it is from power on until the ICE starting for warming up (approx 12 seconds)
    • you can enable the EV-Drive Mode during this S0, if the conditions are allowed so (refer to your owner's manual)
    • the EV-Drive Mode can not be turn on when (1)the temperature of the hybrid system is high (ie; the hybrid battery is above 46C), (2)the temperature of the hybrid system is low (ie; the hybrid battery is below 0C), (3)the hybrid battery charge level is low (three bars or less), (4)the windshield defogger is in use or (5)the engine coolant temperature is below 0C (maybe 20C on the US Prius)


    In Mass here in the morning it is like 20~ degree F. Seems like both factors contribute to it. ;)

    So EV mode is more useful in the summer... :)
     
    #15 Roger T, Dec 30, 2014
    Last edited: Dec 30, 2014
  16. fuzzy1

    fuzzy1 Senior Member

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    ^^ Ken's point here:
    is the same 68F threshold to which I was referring. It is 68F (20C) in the U.S, 32F (0C) in most of the rest of the world. In my climate, this threshold locks me out of EV mode about 360 mornings per year. I've had little opportunity to explore a separate battery temperature threshold, my garage is nearly always above (barely) freezing.
     
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  17. Roger T

    Roger T Member

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    That got me thinking. Why does Toyota set a higher threshold for the US??
     
    #17 Roger T, Dec 30, 2014
    Last edited: Dec 30, 2014
  18. bisco

    bisco cookie crumbler

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    ah, the age old question...
     
  19. bisco

    bisco cookie crumbler

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    we suspect the u.s. legal system, but in this case?
     
  20. fuzzy1

    fuzzy1 Senior Member

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    I suspect it is related to our better hybrid battery warranty.