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  1. duanerw

    duanerw senior member

    Joined:
    Feb 21, 2005
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    Location:
    lexington ky
    Vehicle:
    2013 Prius v wagon
    Model:
    Five
    I went to my toyota dealership on the 17th for my recall.I know the tech well and as i was going on the road the next day he worked me in.I havnt received my recall in the mail but he did it for me anyhow.
    I stayed by the car most of the 2 hrs it took and he went by the book,page by page,This was the first one he did under this recall.As i said i know him well and trust him more than anyone i know.He did both updates on the computers one about 30 min and the
    other about 20.my car was made in nov 04 and i purchased it jan 31 2005.
    I went on my trip the next day which was 840 miles.On prior trips i got 54 mpg and on this one i got 48 up and 48 back not counting running around when i got there.
    When i got there i checked my tires and found 29.5 all the way around.dam oil change.I told them 35 and 33 and the guy that did the oil change said he did as i said. I know I should have checked so dont give me hell.......
    while there i went to the goodyear store and he made sure i had 35 front and 33 rear.
    i have comforttread and they dont recomend higher than 35. 33.
    with the proper preasure i returned home and got the same mpg 48 as i got with low preasure.
    I never have had a problem with the car and wish i had not done the upgrade as i lost mpg.
    im not recomending you have it done or not just letting you know how it went for me
     
  2. tumbleweed

    tumbleweed Senior Member

    Joined:
    Oct 3, 2005
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    Location:
    Eastern Oregon
    Vehicle:
    2010 Prius
    Model:
    V
    Any other possible explination for the decrease in milage? A drop in temprature, wind, anything like that? Let us know, after a few more tanks, if it is still lower than it was.
     
  3. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
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    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
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    N/A
    I'm not willing to accept that it will affect gas mileage with one example. I think I mentioned in another post how unfortunate it is that this SSC is coming out just as the weather is turning colder in most of the country and people will, no doubt, see a decrease in gas mileage and will probably want to attribute it more to the SSC than to the weather.

    I think the only way we'll really know is by comparing to prior similar months.

    I am especially skeptical in your case b/c the affect on fuel economy shouldn't really be significant for highway driving since the ICE runs more or less continuously anyway.

    Here's the thing. Supposedly the flash 'encourages' the ICE to continue running longer/delays ICE shut off at low speeds and stops. Thus, in city and low speed driving you'll have longer ICE-on times and thus more fuel burned and lower mileage. But with a hwy drive the ICE is on mostly continuously and there should be no reason for any affect/impact on mileage.

    Regarding your recent trip specifically I agree that wind, weather, and other factors may be the major players...you definately should have seen an improvement in fuel economy by boosting the tire pressure to spec. Since you did not that strongly suggests that you had a head wind or colder temps or something holding that mileage down.
     
  4. hdrygas

    hdrygas New Member

    Joined:
    May 22, 2004
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    Location:
    Olympia Wa
    Vehicle:
    2004 Prius
    Also when did you do fill ups? I just took a 3-4mpg hit last tank because of the switch from summer gas to winter formula that happens in October around here. Same thing last year. Temps a little cooler but still in the 50's in the AM. When do you change to winter formula in your area? I have not got my letter so I should have a good base to compare with when I get my recall.
     
  5. NiMHPrius

    NiMHPrius New Member

    Joined:
    Jul 7, 2004
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    Location:
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    Don't worry,

    The update they do to the computer recalibrates and reset some of the internal flash memory that keeps a running log of various parameters of the car. The fuzzy logic in the software will take two to three refills of gas to eventually "recalibrate" itself and you will see your mpg go back up. That's exactly what happened to me. I also complained about this and someone on this forum told me the same thing I'm explaining to you know.

    Take care

    HiMHPrius
     
  6. Marlin

    Marlin New Member

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    2005 Prius
    But didn't all the reported stalling problems occur on the highway rather than at low speeds and at stops?
     
  7. efusco

    efusco Moderator Emeritus
    Staff Member

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    Didn't occur at stops, but it can occur at low speeds if trying to accelerate--it's the sudden demand that can't be met that causes the problem.
     
  8. DanMan32

    DanMan32 Senior Member

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    Part of the recalibration changes the power balance. Even now, when loads change, I find my MPG appear lower than it should, but soon the SOC goes to green, and then the ICE runs at lower power.

    So, yes, you can see lower MPG even at highway speeds, but should eventually even out, especially when the ECM and HV adjust their trim.
     
  9. Ron K

    Ron K Junior Member

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    Aug 1, 2004
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    Location:
    Yorba Linda, California
    Vehicle:
    Other Hybrid
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    N/A
    I am on my first tank post re program and also notice a substantial city loss, from Mid 40s to high 30s. admittedly only a 100 or so miles

    I don't suppose we can revert (I never had a problem with stalling anyway)

    Ron
     
  10. LaughingMan

    LaughingMan Active Member

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    I have a Prius manufactured in May 2005, so I didn't have to do the update...

    But I have to wonder if after the update, if a Prius manufactured during those affected months basically is brought to the same software as my Prius.

    So... do the 2004 and early 2005 Priuses now behave like my car in terms of how it handles the ICE?

    Interesting...
     
  11. paprius4030

    paprius4030 My first Prius

    Joined:
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    2012 Prius
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    Two
    Laughingman, I'd be interested to know that also. I got an 05 manufactured in July, and I didn't notice anything different between the new one and the 04 I traded in that was never flashed.