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Gen I stealth question

Discussion in 'Generation 1 Prius Discussion' started by kmc6566, Oct 21, 2010.

  1. kmc6566

    kmc6566 Junior Member

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    Have a question for the Gen I owners. I have a really good feel for my Gen II (2009). I can get almost 60mpg per tank. I attribute that to the fact that there are stretches I drive where I can get into stealth mode for pretty long periods.

    I bought a Gen I about a year ago and we have put about 12,000 miles on it. We love it and have been getting just over 50mpg. Which is awesome. But I feel the reason we don't do better is because I can't seem to get it in stealth mode for more than 1/2 a second.

    When we first got it I thought it might be the tires and the alignment. The tires were not great and the alignment was off. But I finally got new tires and an alignment but still can't keep it in stealth mode.

    Basically what seems to happen is that I find the correct spot with the gas pedal but as soon as I do the car will tend to slow down a lot quicker than my gen II. So once that happens the electric battery kicks in and gets me out of stealth.

    There also doesn't seem to be much play in the gas pedal in stealth mode. What I mean by that is this. In my Gen II I feel like I have some margin for error to keep it in stealth. The height of the gas pedal can be off a little bit and stay in stealth. But with the Gen II, if I move the pedal even a millimeter up or down it takes it out of stealth mode.

    Sorry to be long winded about this. Basically my question is does this seem to be "normal" operation for the Gen I? The aerodynamics are not as good as the Gen II so I could understand why it doesn't roll as well and stay in stealth mode longer.

    But I was wondering if maybe something was off with the gas pedal mechanically. The car does have over 150,000 miles on it and if something was worn out then maybe the link between the pedal and the computer might be off.

    I know I'm not explaining that well.

    Like I said I am very happy with the MPG I am getting on the Gen I. Just wanted to double check that it is operating normally in regards to getting into stealth mode.

    Let me know if you need any other information from me to better answer the question.
     
  2. mlibanio

    mlibanio Member

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    Hi there,
    well it seems to me your mpg is quite good actually. Gen 1 are a little harder to get into stealth mode than Gen 2's, there is no doubt about that. However, I am frequently amazed by my Prius' ability to go stealth for about 3-4 kilometers, even though Toyota said it can only do about 1.5 kilometers if I am not mistaken. My car has almost 200,000 kms right now, and she still loves to run about 46 mpg for me. But I never drive for economy. I am insane about doing tune ups and oil changes and my cars are gems. I have a 2002 Chrysler Neon that gives me about 38 mpg on a regular basis, but my wife and I drive at about 120 km/h or 75 miles per hour with both cars.

    I would suggest checking your 12 volt battery condition. Believe it or not, this battery could be causing your trouble. Put your MFD display screen in diagnostic mode (you can check on how to do this on Prius Chat, lots of pages dedicated to this!). When in the correct menu, you will see your 12v battery charge level, just leave key in ACC, and if it is lower than 11.8 volts, its time to replace it. A low 12 volt battery will make our Gen 1's behave abnormally. In really cold winter weather, you will probably get really crazy mfd or radio performance. Just an FYI!

    Oh and the drag coefficient of our cars is not so bad, and should not really affect its ability to go stealth.
     
  3. justkyle

    justkyle New Member

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    Congratulations! It does sound like your commute might be a tedious one otherwise.
    Which also happens to still surpass the E.P.A.'s estimate of MPG for that model and year. One of the regular commentators gets about that on mileage for his Gen 1 prius. I have not mentioned my mpg yet, for I haven't done the definitive old-school method of figuring mileage. That's right folks, I'm too cheap to fill up twice in a row, on any car :D
    So, my question to you is, are you going by just the onboard computer, or are you doing the old school calculations for mileage that I haven't even done for my prius yet (give me a break, I just picked it up a couple of weeks ago)?
    Just so I'm clear on this, what you're stating is that the Gen 1 seems to kick out of electric mode quickly, and go over to ICE mode, right?
    You didn't mention much else about the car other than age and mileage. How new is the HV battery? Do you have any warning lights on the MFD display? How long does the blue radiator light stay on?
    True about the aerodynamics, but I actually kind of like the look of the Gen 1 prius. Must be just me.
    It is possible, however, I would place my bets on not likely. The gas pedal usually is in one of the most protected areas of the vehicle (the cabin area) and isn't exposed to the harsh elements. More likely would be an investigation of the throttle body, if you haven't done so already. But, then again, you are getting decent MPG out of the vehicle, so it's probably OK.
    That's OK. We can ask questions, too ;)
     
  4. w2co

    w2co Member

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    "Sorry to be long winded about this. Basically my question is does this seem to be "normal" operation for the Gen I?"
    We also own both an 03 and an 06, and what you are seeing is exactly what we see as well. The GEN2's were redesigned from the GEN1's mistakes if you will, and the efficiency proves it. I think you have no problem in your GEN1, and if you're getting 50mpg that's about all you can get out of it! Ours is also at 50mpg exactly averaged over the last 650 miles. Nothing wrong with that. I would keep the tire inflated well, and change the oils on schedule is all.
     
  5. adric22

    adric22 Ev and Hybrid Enthusiast

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    1/2 a second? This is not consistent with my results on the '02 that I recently sold. I could often go half-a-mile on stealth mode as long as it was flat-ground. But mine had a brand-new HV battery.

    Is it possible the HV battery in yours is nearly at its end-of-life?
     
  6. w2co

    w2co Member

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    A brand new HV battery would definitely increase EV mode range. Our 03 still has the OEM pack and is still ok but I'm sure that the new pack would make a big difference.
     
  7. kmc6566

    kmc6566 Junior Member

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    Thanks for all the responses.

    The 12V battery is new so that is not the cause.

    And the traction battery is the original but I have checked the voltages on all the cells and they were excellent according to what I have found on other threads. Lowest cell was 7.63 and highest cell was 7.65.

    Just so I'm clear on this, what you're stating is that the Gen 1 seems to kick out of electric mode quickly, and go over to ICE mode, right?

    This is what I mean in response to that question. When I get into stealth at say 35mph for example. I will be on flat ground but the cars speed will drop very quickly which if the gas pedal remains in the same place will force the ICE to kick in.

    On my 2009 the car glides very well and at 35mph on flat ground will not lose speed quickly and will stay in stealth mode.

    So overall it sounds like it should probably glide better in stealth mode. But if it had a problem I would probably not get the gas mileage I'm getting.

    By the way I do calculate the gas mileage myself and the 51-52 is my calculation not the computers.

    I'll make sure there is no drag from the brakes but I would think if there was my gas mileage would be worse.

    Which is why I was thinking maybe it had to do with how the gas pedal is communicating with the computer.

    That was just a shot in the dark.

    Thanks again for all the responses.

    If I figure out something that does increase my stealth mode I will let everyone know.
     
  8. w2co

    w2co Member

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    If it's any consolation, our 03 does the exact same thing.. Noy able to hold EV mode for very long, it never has that I can remember. As mentioned the GEN2 was a redesign with improvements over the GEN1 even though they have practically the same drivetrain. If you're getting 50-52mpg I would not do anything -it is completely normal even above normal for a GEN1! Ours is at 50mpg but only when I drive it hee hee, when the wife drives it, it goes down from there..So driving habbits are a big factor as well. ie: a lead foot will be repaid at the gas station.
     
  9. w4y

    w4y Junior Member

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    I think there is a bit of confusion on semantics in this thread. I believe what the OP is meaning to say is "no arrow stealth" or "glide". In which case, I've experienced what the OP experiences. Your foot will learn the throttle glide position with experience, and it'll become easier. However, yes, it's not as easy as the glide in Gen 2 below 41 MPH.
     
  10. kmc6566

    kmc6566 Junior Member

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    Yes, that is what I mean. When you have no arrows. That's what I call stealth mode. And it seems much harder to get there in the gen I. In fact for me it's almost impossible to keep it there.

    At least compared to my Gen II.
     
  11. marzprius

    marzprius Junior Member

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    I bought my wife an '01 to replace her Echo 6 mo. ago, we love it too. I've had my '06 since new. Yes, it's much trickier to maintain the no arrows mode in the '01, & well documented here. The main reason is the dual wiper accelerator sensor on the 97-03 & the Hall Effect sensor on the 04-present, as well as software differences too.

    It does get easier with practice on the gen I, & my wife thinks it's child's play when she drives my '06!
     
  12. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Maybe I missed the memo: What is wrong with "N"?

    If you want a power off glide and under 42 mph:

    • foot off accelerator - so ICE will shutdown
    • wait ~1/2 second - give it a little time to get the ICE off
    • shift into "N"
    If going over 42 mph indicated:

    • shift into "N"
    If going down hill and you're in "N," and ICE off and speed approaching 42 mph, shift into "D" until ICE is running and then shift into "N". This is to avoid reported over rev of MG1. I've gone up to ~50 mph but I don't recommend it . . . unless you want to go into an experimental region that has not been mapped.

    I'm going on 5 years with our 2003 Prius and still running ~52 MPG. I don't 'glide' except in the morning while the ICE warms up.

    Bob Wilson
     
  13. kmc6566

    kmc6566 Junior Member

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    Good idea Bob. I hadn't really thought of shifting into neutral.

    I'll try that and see how that works out. That would also give me some feedback into how it is rolling. If after putting it in neutral it still doesn't roll well then I can check out the wheels.

    I'm not getting any noise from the wheels but that could still mean the wheel bearings are going bad and just not rolling that freely anymore.

    Thanks.
     
  14. w2co

    w2co Member

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    Ah yes sorry for the misunderstanding, and it is still the same answer, it is much easier to get into and hold "stealth" mode in the 06 vs. the 03. I don't think our 03 has been in that mode for more than a second or two at random places and conditions during it's entire life. It's always either in ICE mode or EV mode but not for long. One thing I have not grasped yet is that when in stealth mode is mg1 feeding current straight into mg2 to keep the forward motion with no charge going to the battery? Or is all just coasting and doing nothing? Regardless it can be done easily in the 06 after it's well warmed up and flat to slightly downhill grade or even a slight tail wind. In the 03 it doesn't do that much at all. BTW in the 03 when I'm close to parking, and I see the SOC is only around 55 or so, I purposely drive down a pretty long hill nearby with light regen braking to boost charge the pack up to 59 or 60 SOC before parking. That I believe will extend the life of the OEM pack.
     
  15. adric22

    adric22 Ev and Hybrid Enthusiast

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    I think the confusion here may be about your terminology. (or Mine..) I'm under the impression the consensus among Prius owners is that "stealth mode" is when the prius is operating entirely on electric power, driving around with the engine off. Typically this would be when the car chooses to enter this mode, versus when the EV button is used, in which case we would refer to that as "EV mode."

    You seem to be describing a scenario where the car is essentially coasting without doing any regen or sending any power to the wheels. Yes, that does take some very precise foot work on the throttle to get into that state.
     
  16. w2co

    w2co Member

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    Thanks for that and yes I have always confused the two. To me EV (electric vehicle) usually reserved for those vehicles that only have battery power and no ICE at all, but must be recharged regularly, and have a definite range limit. To me in a prius EV mode means ICE is off and the vehicle is moving on electric only, simple enough huh. Now this "stealth" mode, also known to me as "hypermilling" is where there are no arrows on the display (no electric power going in or out) yet the vehicle is still moving forward seemingly on it's own minute power being generated internally, barely overcoming resistances, usually at speeds above 35 but less than say 45mph. I still have yet to understand how it does this, but I have seen it much more frequently in the GEN2 of course. I think the GEN1 has done it in the past as well but much less frequently. The conditions must be just right for it to even occur, slight tailwind, proper tire pressure, correct gas peddle position, proper warm up stages etc. and because of the losses and frictions and road resistance involved I don't think it can sustain for very long even in the GEN2 on a perfectly flat surface. But it does represent totally free transport for a short time though. Does anyone know if this mode involves power from MG1 that would normally be charging the hv battery but instead is redirected directly to MG2 for forward drive? That is the only way in my mind how it can even happen.
     
  17. justkyle

    justkyle New Member

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    It should be noticed, that in some states operating a moving vehicle while in Neutral is (queue ominous music here) against the law!

    That being said, how often are you driving with the police riding side-saddle anyway?

    I guess, the case could be made in event of a wreck, they could use the car being in Neutral against you in court.

    So, I guess check with your local DMV..

    Kyle
    02 Prius
    being repainted this weekend.
     
  18. bobofky

    bobofky Member

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    I think that there must be some difference in the Energy Displays between Gen 1 and 2. I have a 2001 Prius and often see the "no arrows" state, but that is when I am coasting with no power of any sort being applied. The state is sensitive to speed and terrain. If coasting speed increases the regenerative mode kicks in and arrows will show current going into the battery. If the speed decreases the ICE will start and put current to all components. To me, "Stealth" is when the car is going on silent electric power only.
     
  19. john1701a

    john1701a Prius Guru

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    Stealth. It's interesting reading the various definitions from the variety of owner perspectives. Here's the official one:

    Electric-Only driving (up to 42 MPH for Classic & Iconic Prius, 46 MPH for 2010) without the engine in motion.

    It's easier to understand why the term came about if you know when it happened: August 1, 2000. The automotive world was quite different way back then. Very few even knew what a hybrid was. That new category of vehicle needed new design identifiers to keep misconceptions from overwhelming the rollout effort and supporters embraced the fact that most people wouldn't realize "stealth" was actually a double entendre. They'd just assume it was meant to point out the smooth & silent mode.

    The second meaning took stealth to a higher level, where Prius would push it's way into the mainstream catching many totally off guard. And sure enough, the second generation model ended up causing the industry to panic. They had no idea a hybrid would stir so much interest or that the technology would prove both reliable & profitable.

    Pretty sweet, eh?
    .
     
  20. hybridtwins

    hybridtwins Member

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    This is the definition I've always gone by, and I can keep my 2002 in stealth for considerable distances. But I seem to recall someone on PC saying that trying to force the system into stealth for long periods can be detrimental to fuel efficiency, since the ICE will eventually have to make up for this to charge the HV battery ("Ya canna change the laws of physics!" -Scotty). But correct me if I'm wrong on this.