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Car is a bit jerky uphill at low speed

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by CivicQc, May 1, 2010.

  1. CivicQc

    CivicQc The world needs more prius

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    I notice it nearly every time I am starting from a red light, uphill. As I accelerate, the car starts moving, and the first few meters are a bit "jerky", as if the transmission was slipping. Just a bit. Let say the ride is not as "smooth" as at higher speeds. Reading other threads, I understand that the Prius transmission cannot "slip".

    Can it be just because of the low rpm of the ICE?

    Anyone else experienced that?
     
  2. john1701a

    john1701a Prius Guru

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    If you accelerate slow enough, you can notice the engine startup.

    Acceleration using only electricity at first isn't the most efficient use of that battery though, so the informed owners tend to avoid that by being more generous with the pedal. After all, excess engine power is used to recharge and its the overall use that counts anyway. A brief firing up of the engine to get up to speed then have it shut off sooner can actually use less gas in the end.
    .
     
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  3. dtuite

    dtuite Silverback

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    Do you use the hill-holder feature on the brake pedal?
     
  4. adamace1

    adamace1 Senior Member

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    It's the ICE starting.
     
  5. CivicQc

    CivicQc The world needs more prius

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    Yes, I do. But not always. The jerky effect occurs in both cases.

    No, I don't think so. I am pretty sure I feel the ICE starting after that (I will double check this week). The ICE starting is a very quick feeling (it does not last very long), whilst what I describe lasts longer, depending on how long I stay at low speed.
    Note that I have also noticed it once after slowing down uphill, maintaining a low speed, about to stop at a red light.
     
  6. qbee42

    qbee42 My other car is a boat

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    It's the hamsters falling backward in the wheel. This is more noticeable with the 2010 because it has two hamsters in the squirrel cage, where the Gen II Prius only has one.

    Tom
     
  7. Jolly Paul

    Jolly Paul Member

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    I've upgraded my G3 with three after market rabid gerbils.
     
  8. CivicQc

    CivicQc The world needs more prius

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    Oh, I understand what the acronym HP stands for now! HamsterPower! :)
     
  9. CucamongaPrius

    CucamongaPrius Junior Member

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    I have a 05’ with 157000 miles. As I accelerate, the car starts moving in electric mode until it reaches 14 mph. Then I noticed the engine starts up and at a low acceleration the feels like it is slipping. But if I press on the accelerator harder it speeds up fine. It is only jerky when press the accelerator slightly. The check engine light lit up once and turn off quickly Has anybody had this happen to you? And what was the cause.
     
  10. eric1234

    eric1234 Active Member

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    I've felt and described a low-speed (in electric mode only) vibration at the very start of motion (somewhere between 0 and 1 mph)...No one has clearly commented on either the cause or whether it is a problem to which any attention need be paid. I liken it to traveling over the "vibration ridges" on the highway shoulder, but not nearly so severe.
     
  11. The Critic

    The Critic Resident Critic

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    I have noticed smoother acceleration (less abrupt engagements) ever since I had a transaxle drain and refill done at 15k.
     
  12. adrianblack

    adrianblack Member

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    Yep, it's the poles and permanent magnets in the electric motor. You can feel it better on a steep hill when starting to move. (If you've never noticed it.) Totally normal and all Gen 3 cars I have been in do it. First time I noticed it was on a steep parking ramp -- was worried at first. If you know how it feels you can feel it on every start, even on flat roads. Have driven several other Gen 3 cars and they all feel exactly the same way.

    It comes from MG2 at speeds just above 0 RPM. (In forward or reverse)

    On a steep hill, you can actually get right into the sweet spot and hold it at that speed and it'll keep doing it. On flat ground it's harder because as soon as you apply power the motor spins past the particular RPM and smooth out.
     
  13. eric1234

    eric1234 Active Member

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    Yes! That is my observation exactly. Once you "find" it, it's alarmingly 'obvious' - even if it is a bit elusive...
     
  14. bear4

    bear4 Junior Member

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    I just made another post I believe about the same issue, sorry, did not see this one first. I noticed the same vibration at very low speed in electric mode just a few days ago, my Prius has only 700 miles on it, and I was very alarmed. It felt like something is slightly lose inside the transmission, and it only happens between 0 and 2 mph. Being so quiet, it is a lot easier to notice very faint sounds and vibrations in Prius than in any other car. I can ride the brakes and make it do it longer, and I was ready to take it to the dealer, now I am glad I found this thread.