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engine seems to run roughly

Discussion in 'Gen 2 Prius Technical Discussion' started by ~newpriusowner~, Aug 27, 2010.

  1. ~newpriusowner~

    ~newpriusowner~ New Member

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    I just bought my first Prius, a used 2009. So far I like it very much. I just have one concern: The engine seems to run roughly, especially when it's idling and when it goes up to about 45mph. I'm not sure if this is normal for a hybrid and I'm just not used to it or if it indicates a problem.

    The problem persists even after it's warmed up.

    Can anyone fill me in about this?

    Thanks very much,
    Molly
     
  2. 2009Prius

    2009Prius A Wimpy DIYer

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    I test drove quite a number of 2009 before I bought mine and I would say the engine should not run roughly, at least not for more than a few seconds - in some conditions when the engine shuts off or starts up you may feel the "rough stop" or "rough start", which are normal, but if the engine runs roughly continuously while the car is moving at speed then that does not sound normal. Just my 2 cents. Good luck! :)
     
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  3. Politburo

    Politburo Active Member

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    If you're not seeing any malfunction indicator lights (check engine and/or a big red triangle), then it probably isn't a big problem.

    But it really shouldn't be running roughly after warmup..
     
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  4. ~newpriusowner~

    ~newpriusowner~ New Member

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    Thanks so much, Politburo and 2009Prius, for your replies.

    I can give a bit more info:

    I have been concerned about two maybe-related and maybe-not-related things: 1. subtle sounds and feeling when idling, and 2. a feeling (don't think sound also, but not 100% sure) when driving, especially at speeds ~42 – 48 mph.

    About #2.: I had already been told by a mechanic, who has never owned a prius but works on a good number of them, that the groove pattern in the tires is a bit distorted from wear (he says that it seems like priuses go through tires faster than other cars), which would likely lead to slight vibration in the steering wheel. Later, he drove my car. He said he agreed it was feeling rough, but said it was probably the tires, even though he understood why it would have seemed like the motor to me. He thought it was probably OK.

    About #1.: To give more description--After I turn the car on, while still in park or neutral (so tires would not be relevant), it has a SLIGHT feeling and sound as if it's running faster-slower-faster-slower (sound is changes in pitch; feeling is of a sort of hesitation then running strong). Overall, it goes through two stages, the first lasting abotu 30 seconds, then the second when it "settles down" into a different overall quality/sound. Don't know how long the second stage lasts, because the engine shuts off after idling for ~a minute or two, which I assume is normal for a prius (and good for gas savings). To be clear, though, these overall stage changes I just described are NOT what I'm concerned about; I'm concerned about the faster-slower-faster thing I described above that happens within each stage--maybe cycling once/second or so.

    I hope this information helps. It’s entirely possible I’m being overly sensitive; it is slight, afterall. And maybe this is normal for a prius. Also, my last car was a diesel, so haven't had a gas car for several years and might have forgotten what they sound and feel like. Just not sure.

    Are your verdicts still the same after hearing this?

    Thanks very much,

    Molly
     
  5. cwerdna

    cwerdna Senior Member

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    The faster and slower behavior you're encountering when engine warming up is normal on the Prius. Yes, it runs roughly during that time and RPM goes up and down. IIRC, it corresponds to stage 1a of http://priuschat.com/forums/attachm...ference-aid-priusstagemodereference051408.pdf (from http://priuschat.com/forums/knowled...perating-mode-availability-reference-aid.html).

    I have a ScanGuage and can definitely see IGN at -10 at startup. But, I don't usually leave that gauge up nor monitor it anymore, for most of my drives.

    The rough ICE shutdown that 2009Prius mentions can be a bit startling and sometimes very rough. It can almost sound like the car is dieseling (like the knocking sound you hear from overheated cars right after they've been turned off).
     
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  6. That_Prius_Car

    That_Prius_Car Austin Kinser

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    I know the feeling, it feels like it misfires or a jerking. This is normal and it does not feel like thart all the time. To my surprise, my 2007 has not gave me that feeling yet. What's weird is that yesterday on my way to the park, I set the cruise at 43mph purposely so keep the engine running at an efficient manner so that way I wouldn't run the battery down and induce the engine into heavy charging. Anyways, I was cruising at 43mph and my Energy Monitor was telling me that the engine was purely powering the wheels, while also sending charge to the battery. This is a fairly normal operation the Prius will select while cruising and I was getting between 53-57mpg. (As you might have seen from some past pictures, I live in the flat lands of IL. No hills at all.) Back to my story, my battery had 6 blue bars which is usually where the Prius feels most comfortable so it was fairly normal. About 5 minutes later, I looked back at the Energy Monitor, this time I had 7 green bars "Hmm, it must have charged more than it wanted." So I expected the car to start using more electric and for my mpg to climb, nope. She kept on charging. I kept a close eye on the SOC (state of charge) and before I knew it, BAM!, all 8 green bars where there! After it hit all 8 bars, it used EV mode very aggressively, even though I had my cruise set at 43mph. I took some photos of this event and will be happy to share them with you. Apparently, it's a battery reset of some sort that the Prius does every few thousand miles. I don't know if any of you have experienced this, but yeah.
     

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  7. ~newpriusowner~

    ~newpriusowner~ New Member

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    Thanks so much, That_Prius_Car, and cwerdna, and the others before you as well, for your replies. This is all very, very helpful!

    Molly
     
  8. That_Prius_Car

    That_Prius_Car Austin Kinser

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    Hey, that's what were here for. :)
     
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  9. cwerdna

    cwerdna Senior Member

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    One more reply "The engine seems to run roughly, especially ... when it goes up to about 45mph". What if you sit in park and rev the engine? Is that the roughness you're talking about or is it possibly from feedback via the tires and suspension while moving?

    If one is used to the superior NVH (noise, harshness, vibration) levels from inline 6, V6 or V8 engines of non-sports cars, esp. luxury cars or family cars, then the NVH of 4 bangers like in the Prius will be disappointing. It's not just the intensity of the noise, but it's also the sound of it. I can totally relate since I miss the power and smoothness of my 02 Maxima's 3.5L 255 hp V6.

    Maybe you can meet another 2nd gen Prius owner in the area and have him ride along or swap cars briefly and compare notes? I'd offer to except I'm on the other side of the country.
     
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  10. hyo silver

    hyo silver Awaaaaay

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    I'd start with changing the oil.

    If you don't know the repair or maintenance history, this is cheap insurance. Mine *seems* smoother and quieter on synthetic, but I suppose it could be my imagination. :)

    It wouldn't hurt to check the electrical, too, to be sure everything is functioning within normal parameters.

    Plus, I'd highly recommend new tires. They're a small percentage in cost of the car, yet they make a huge difference in performance and safety.
     
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  11. 2009Prius

    2009Prius A Wimpy DIYer

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    Check the tire pressure. There are some threads about Prius tire wear and inflation pressure. The general consensus is that the Toyota specified 35 psi does not seem enough to keep the tire from uneven wear so slight over inflation is recommended. Some use 40 front 38 back and others 42-40. The max is specified at 44 for the OEM tires. Good luck! :)
     
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  12. ~newpriusowner~

    ~newpriusowner~ New Member

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    That's a good idea. The mechanic who rode with me (see my second posting, a few lines down) said exactly that. This would be a good way to test it out to see if he is correct. I'll do that the next time. Thanks a lot.
     
  13. ~newpriusowner~

    ~newpriusowner~ New Member

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    These are good ideas. Thanks. I'll have to put snow tires on it shortly (we are in snow country here), so I'll have a chance to see if that makes a difference.
     
  14. ~newpriusowner~

    ~newpriusowner~ New Member

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    Another good thought. Thanks a lot.

    (I think I'd better bone up on all the acronyms I've seen people use. :). What's OEM? Is there a page/posting somewhere with a prius forum acronym glossary? :))
     
  15. Rae Vynn

    Rae Vynn Artist In Residence

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    OEM is pretty common - it means "Original Equipment Manufacturer"... so, if you buy a Toyota oil filter, you are going OEM with the filter... etc.
     
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  16. 2009Prius

    2009Prius A Wimpy DIYer

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    Google is my friend. ;) The first item I got when I typed in "oem":
     
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  17. ~newpriusowner~

    ~newpriusowner~ New Member

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    Ah. OK. Makes sense. Thanks for the translation.

    (And I love your very pretty headpiece, BTW. :))
     
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  18. ~newpriusowner~

    ~newpriusowner~ New Member

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    Oh. Great idea! Google the master glossary! Thanks!