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Latest Software Update Safety Recall Resulting in 8mpg less...

Discussion in 'Gen 3 Prius Fuel Economy' started by ravencr, Apr 13, 2014.

  1. Mendel Leisk

    Mendel Leisk Senior Member

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    It might be a problem during warm up period? Does stellar when warmed up only? Hang in there.

    Or just maybe it'll do good for the rest of the tank? Think good thoughts. :)
     
  2. Larry Schnack

    Larry Schnack Junior Member

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    They warmed it up before we started, unless it gets some supper warmth long after the engine is warm, batteries are full, and it has been using EV mode for awhile. ;o)
     
  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Perhaps your first step is to replicate at least two points of my benchmarks:
    [​IMG]
    • Identify flat routes at least 10 miles long with no stops and periods of no traffic.
      • There may be a by-pass loop that would also work.
    • Practice drive the route to identify the start and end gates and no traffic delays.
    • First pass - reach target speed; reset trip meter on entrance gate, and; photo meter at exit.
    • Second pass - reverse direction, reach target speed; reset trip meter on entrance gate, and photo meter at exit.
      • If you have a loop, a single pass using the same gate for start and stop works.
    • Average two passes including verification the trip meter shows the same cruise control speed.
      • Post photos here and I'll show the most accurate calculation approach.
    If you are still interested in the problem, I'll work with you BUT you'll need to confirm that the car can achieve its rated performance in your hands. Doing the benchmark means you are committed to finding out what is going on.

    After a successful benchmark, you'll need an OBD recording scanner that knows the Prius codes. My preference is a miniVCI and Windows XP to record metrics. There are also IOS/Android tools like Torque but I don't have experience with them. We use the machine to record the metrics for post test analysis.

    Bob Wilson
     
    #383 bwilson4web, Oct 23, 2015
    Last edited: Oct 23, 2015
  4. Larry Schnack

    Larry Schnack Junior Member

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    I would still like to know if others are still having the problem, and I would like to know. I know from the first posts in this thread and other forums that others have had this issue, and that dealers and the 800 number had acknowledged issues related to this. Since the VW scandal, I am not sure I trust the results that Toyota corporate did on my car. In less than optimal conditions, with their equipment attached, my car had the absolute best round trip millage ever, even before I had the software recall update. Even the previous test drive by the dealer (no machine attached) was much worse. Once their machine was removed, the millage went right back down, and has stayed that way.

    I know the MPG calculation can't be trusted (I have absolute data on this) and I am not sure if Toyota Prius codes can be either. Wouldn't their external machine basically take the same information and have very similar results. They said there was more accurate GPS on their external machine. In reality, actual car millage driven and speed is more accurate than an external GPS (GPSs don't know exact positions of the satellites as they drift and get repositioned) . How does the machine really measure distance and gas used, if the onboard computer can't?

    I still believe that running the car thousands of miles and dividing it by the number of gallons is a good and truer measure than the onboard computer or their test, and it is showing a big loss in millage after the recall. Am I really the only one with this problem at this point?
     
  5. gliderman

    gliderman Active Member

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    The computer on my car lies. I get between 3-15 mpg difference calculating from fillups. MPG is always about 5 mpg lower than indicated.
     
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  6. neez

    neez Member

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    I have a 2011, and i got all the latest software updates last summer. I've had no issues with fuel economy or changes whatsoever. I get 48-50mpg on my daily commute spring-fall, i get about 45mpg in the winter on the same commute. Though i mostly drive highway around 60-65mph with some country backgrounds mixed in. The fuel economy guage on the car is well known to be about 3-4% optimistic. But i also have a long commute, about 40miles 1 way, then 40 miles back in the afternoon. Long commutes general give very consistent results due to the time it takes to warm your engine being less of a ratio of the total time of your commute. My sister borrowed my car for a couple weeks while i was out of town and the overall mpg meter for her was 42mpg on my car. But she only has a 15minute commute and all the local shopping areas are within 10 minutes to drive, so all her trips are short. Before i left for my trip, the meter said 53mpg, she dropped it alot.

    At least in my car, i don't think there's any kind of a cheat software like VW.

    As for the GPS speed, i think it's consistently more accurate, even using WAAS. My speedometer is about 1-2mph low, which might be because of tire wear, tire size, tire inflation, other factors etc... In my experience with GPS, even if location has drifted, the position relative to each other is still pretty accurate. We use an RTK base station at work, but even with just WAAS the actual location may drift a few meters, but the location relative to each other are also drifted. So we can set and A-B line or path and our vehicles will still follow very well. After a few hours, we may have to remake our lines, but for doing gps speed, it should be fine. But in my experience, i would certainly trust a gps speedometer more than my actual speedometer. Most cars i've owned have always errored on the side of being low. As for tripometer though, if the GPS doesn't account for elevation changes, then the cars trip meter may be more accurate.
     
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  7. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Cars have imprecise indicators. If you want accuracy, you'll need after market instrumentation:
    • GPS for speed and distance
    • accurate fuel meter
    • a computer to combine and display and/or save metrics
    Google can quickly find multiple sources and home-grown projects.

    As for @Larry Schnack, I have had to put him on my 'ignore user' list following his example of ignoring advice from either Toyota or folks here. In life there are those who like the preacher and the flood refuse God's TV warning, the Sherriff car announcement, the rescue boat, and the rescue helicopter saying 'God will provide.'

    Bob Wilson
     
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  8. ETP

    ETP 2021 Prime(Limit),Highlander HYB Plat,B52-D,G,F,H

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    No issues on my 2011 and 2012, but I am scared of EPA (extra person around). They have detuned diesels for years to get less MPG and less NO2. Not my idea of progress. We don't need a fix to get less MPG.That nice lady with no picture?:LOL::ROFLMAO: No date for you GI.
     
  9. bwilson4web

    bwilson4web BMW i3 and Model 3

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    This is not quite accurate in the case of VW who in 2014 issued a patch for the TDI diesels. It seems occasionally their cheat-software would accidentally enable the emissions hardware. This led to a number of TDI warranty repairs. So the VW patch actually did a stricter test for emissions testing to turn off emissions hardware. In effect, the 2014 VW patch fixed their diesels to emit more NOx by keeping the emissions hardware disabled. With a straight face, they told the EPA the patch was to avoid failures of their emissions hardware.

    Around June 21, we should see the final agreement on the cheat-diesel scandal. VW has already agreed to have some buy-back of these rolling polluters. But you seem to be under the false impression that they have good MPG.

    Every time we've compared cheat-diesels to the Prius, they have consistently performed badly. At best, they are equal to some of the better, small gas cars that don't dump NOx out the exhaust. So with the cheat-diesels, you can pay more and get less.

    Bob Wilson
     
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  10. felix mizioznikov

    felix mizioznikov Junior Member

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    I recently had my 2012 in for service at 130,000 miles. Got new tires, oil, alignment and cant for the life of me get over 42mpg when I was easily able to get about 55 mpg and could push for 62mpg in slower roads. tires are all at 38psi nitrofill.
     
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  11. gliderman

    gliderman Active Member

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    I never got over 50. But 42 is about the best I can do now with normal driving. Used to be 45-48 mpg.
     
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  12. neez

    neez Member

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    What tires did you buy??? I have michelin energy saver A/S tires 195/65/15. My guess is the tires you have are heavier with more rolling resistance. I only run 32psi BTW, 38psi is too bouncy for my liking.
     
  13. ETP

    ETP 2021 Prime(Limit),Highlander HYB Plat,B52-D,G,F,H

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    Tires is my guess. Unless you have the exact same tires and tire pressure there is no way to tell for sure. Like a box of chocolates you never know what you got till you bite in. I love the cherry centers BTW.

    42 is the answer to the ultimate question of the universe. OEMs MIJ is a safest bet.Short list of things that affect MPG:

    1. Correct oil

    2. Tire pressure

    3. Correct tires (LRR OEM MIJs are best)

    4. Rain/snow/bitter cold weather.

    5. AC over usage (setting it on 65 and full fan speeds)

    6. Jack rabbit starts and stops.

    7. Quality of gas

    8. Terrain

    9. Windows down at higher speeds

    10. Cruise control in hilly areas

    11. Weight in the car

    12. eco mode can help some drivers

    13. Windy conditions

    14. Nagy wife

    15. Alignment
     
  14. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Oh I suppose it is worth pointing out that the new, Gen-4, 2016 Prius does not have the patch that some believe is so disastrous in the Gen-3 Prius. New car; new warranty, and; be happy.

    Bob Wilson