05 prius rpm jumps

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ron day, Jan 31, 2011.

  1. ron day

    ron day Junior Member

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    my 05 rpms rise on one road in only one place and no where else. i am going down hill coasting (in drive) and pass over road damage (blacktop St RT 131 Ohio) which sways my car to the left and then imed. back to the right . this then happens one more time within 35 feet. rpms usually go up BUT does not make the car speed up. on1/24/11 on same hill a change occured. pass over "hump" again (always downhill) coasting or breaking and rpms went way up . again, the cars speed in NOT changed. toyota dealer wants me to come in. wants to duplicate rpm reving. Only does it on ST. RT. 131 hill so I told them they can not just make it happen. No codes showed on Autozones hand held computer checking device. At $87.00 an hour I do not plan to let a dealer "play" with it. Anybody else have this problem? any answers?
     
  2. qbee42

    qbee42 My other car is a boat

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    How long of a downhill? Does your HV battery SoC go all the way to full green?

    Tom
     
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  3. ron day

    ron day Junior Member

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    hill is 1/2 mile long. I will have to watch and see if battery shows full green. I will add answer then. Thanks, Ron
     
  4. cwerdna

    cwerdna Senior Member

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    If the SOC hits full green (all bars filled) while going downhill, the engine ICE starting and possibly revving to high RPMs (possibly 2000+) is normal. It's apparently to keep the battery from getting overcharged.

    I encounter this around where I live now due to a steep descent and can monitor the ICE RPMs and HV battery SoC, thanks to ScanGauge. It'll tend to happen ~75% or slightly higher SoC, which is represtened on the MFD as all filled bars.

    And no, all filled bars does NOT equal 100% SoC. Someone figured out the mapping and posted it at http://privatenrg.com/#Full_SOC.
     
  5. uart

    uart Senior Member

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    Yeah you're going downhill for 1/2 a mile so you're regenerating a fair bit of energy. Then you have to slow down for the roadworks and there's some more regeneration. So yes it's extremely likely that this is just the regenerative system dumping excess energy once the traction battery is full.

    BTW. This is nothing abnormal. Many of us here that drive in hilly terrain have seen this happen once or more. Just take a look at the batery charge display next time, it happens if you get all 8 green bars and then still need to brake some more. :)
     
  6. 2009Prius

    2009Prius A Wimpy DIYer

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    Did the RPM stay up indefinitely or did it come back down after a short time? If the latter then it is very likely just that when you passed the "hump" in the road, the traction control kicked in to rev the engine to save the MGs. So no worry. Good luck! :)
     
  7. ron day

    ron day Junior Member

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    thanks for your comments. at the bottom of the hill when I hit the peddle the reving stops. Ron
     
  8. uart

    uart Senior Member

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    That is because at the bottom of the hill when you press the go pedal the car suddenly has an outlet for that excess energy stored in the battery - and that's doing what it's designed to do, to power the car! So it uses the battery energy to propel the car instead of trying to waste it by spinning the engine as an air pump.

    It's all 100% logical and 100% normal. Just take note next time if the battery is at a full 8 green bars when it happens, then you'll really know for sure.
     
  9. donalmilligan089

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  10. donalmilligan089

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    Mine did this same thing but all the warning light. s came on until I stoped and then just the red triangle and check engine light was on until cleared at dealer Is that normal?
     
  11. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    If the lights came on, that's not normal. Since it is summer-weather in most of the northern hemisphere now, have you had the inverter coolant pump recall done?
     
  12. donalmilligan089

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  13. donalmilligan089

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    Yes I have . Tonday it felt as if the regen were coming and going. Sort of a seat of the pants drag you know
     
  14. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Well what codes did the dealer pull? It should be on your receipt/invoice.
     
  15. donalmilligan089

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