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Engine speed higher than before...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by AllenZ, Apr 9, 2014.

  1. AllenZ

    AllenZ Active Member

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    I found recently that my 04' Prius' engine easily goes higher rev than before (based on engine sound pitch). It happens mainly when cold start, go up hill. After warmed up and on flat road, it goes back to normal. Overall, still in great condition at 211K. MPG stays at 46 on meter when temp is around 45F with 50% highway drive at 100 miles/day.

    I suspect the serpentine belt slippery or something. What do you think? I think the belt is original. I bought it used at 104K.

    Thanks!

    Allen
     
    #1 AllenZ, Apr 9, 2014
  2. JC91006

    JC91006 Senior Member

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    An original belt at 200k miles :eek:

    I think you should replace that belt, an overheated engine is not a good thing. Also I don't think your engine speed has anything to do with a loose belt.
     
    #2 JC91006, Apr 9, 2014
  3. nh7o

    nh7o Off grid since 1980

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    Right, it is not about the belt. What does the battery charge level indicate when this is happening? At your mileage, the battery is not far from needing replacement, as so many others are finding now.
     
    #3 nh7o, Apr 9, 2014
    uart likes this.
  4. uart

    uart Senior Member

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    ^^^ +1

    Look at your state of charge while this is happening Allen. You'll probably see it rapidly dropping several bars and when it's down to just 2 or 3 you'll get much increased engine revs, especially if accelerating or climbing.

    I must have given this advice about 1000 times here but I don't think many people are listening. If you want your aging batteries to keep going people, then you'd better start warming the engine when cold (unless only driving low speed on totally flat terrain for the first few minutes). The prius tries to pull all the motive power from the traction battery until the ICE has warmed through "stage 1a", and (depending on speed and terrain) this can punish an aging battery pretty hard.
     
    #4 uart, Apr 9, 2014
    cwerdna and AllenZ like this.
  5. AllenZ

    AllenZ Active Member

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    Thanks all for the info, especially the warming up tip, never throughout about that.

    It's still a mystery to me why the engine rev so fast for a couple of days, when the coldest winter gone, temp at around 40F. Days later, when temp went to 55F, battery feels strong (low speed acceleration very good), and engine back to normal.

    I replaced belt and water pump (getting noisy). Feel like 85% new now. Although still burning oil at 1qt/700 miles, mpg actually get to 50.4 last tank. I drive 95 miles a day, 70% on local at 45 mph. Pretty good for a 214K car.
     
    #5 AllenZ, May 20, 2014
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