1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Poor Fuel Economy After Brake Change

Discussion in 'Gen 3 Prius Fuel Economy' started by Tim Jenkins, Jul 15, 2021.

Page 2 of 5
  1. Tim Jenkins

    Tim Jenkins New Member

    Joined:
    Jul 15, 2021
    25
    6
    0
    Location:
    Dalton, Georgia
    Vehicle:
    2010 Prius
    Model:
    V
    Okay, new idea, I am new to this site, am I allowed to upload a video? If I can, I will test drive my car and record my dash so everyone can see what I am experiencing.
     
    #21 Tim Jenkins, Jul 16, 2021
  2. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,174
    4,079
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    that would be best, we never really read here.
     
    #22 Grit, Jul 16, 2021
    Tim Jenkins likes this.
  3. TheLastMojojomo

    TheLastMojojomo Active Member

    Joined:
    Sep 14, 2016
    232
    177
    0
    Location:
    US
    Vehicle:
    2009 Prius
    Model:
    Touring
    There are a multitude of factors that could cause you not to be gaining speed down the mountains this time around besides regenerative braking.

    • Ambient temperature - Effects tire pressure which effects rolling resistance.

    • Sun/no sun - Effects tire pressure which effects rolling resistance

    • Tail, head, or side wind acting with or against the direction of travel.

    • How sticky the road is.

    It's completely normal when I'm on certain hills in my area, to accelerate or even slightly lose speed going down them depending on these factors.

    To me it sounds like your Prius is functioning completely normally.

    How long have you had your Prius?





    Posted via the PriusChat mobile app.
     
    #23 TheLastMojojomo, Jul 16, 2021
  4. Tim Jenkins

    Tim Jenkins New Member

    Joined:
    Jul 15, 2021
    25
    6
    0
    Location:
    Dalton, Georgia
    Vehicle:
    2010 Prius
    Model:
    V
    I have owned the car for 2 years. I plan to post videos of my dash during a test drive tomorrow so everyone can better understand what is happening. This is not rolling resistance, this is an electro/mechanical issue within the car (and everything points to the regen brake system, IMO). Like I posted earlier, if this is 'normal', than I can never 'coast' and maintain speed, which means I either have to use cruise control (which is not practical in town, in heavy traffic or rain/snow) or I will always be applying pressure to the gas pedal which cannot be efficient. Let me be clear, for example, at 50 mph on a "level road" with no incline, when I let off the gas, I am down to 40 mph in less than 5 seconds.
     
    #24 Tim Jenkins, Jul 16, 2021
  5. TheLastMojojomo

    TheLastMojojomo Active Member

    Joined:
    Sep 14, 2016
    232
    177
    0
    Location:
    US
    Vehicle:
    2009 Prius
    Model:
    Touring
    My next guess then would be it sounds almost like B mode is kicking on without you actually having it on.

    Posted via the PriusChat mobile app.
     
    #25 TheLastMojojomo, Jul 16, 2021
  6. Tim Jenkins

    Tim Jenkins New Member

    Joined:
    Jul 15, 2021
    25
    6
    0
    Location:
    Dalton, Georgia
    Vehicle:
    2010 Prius
    Model:
    V
    That is a very interesting point, is there a way to 'reset' the B gear?
     
    #26 Tim Jenkins, Jul 17, 2021
  7. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,518
    14,128
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    It sound like your brake repairman put the car in POWER mode and you haven't noticed the light on your dash.
    Screen Shot 2021-07-17 at 8.18.45 AM.png
     
    #27 jerrymildred, Jul 17, 2021
    bisco likes this.
  8. Tim Jenkins

    Tim Jenkins New Member

    Joined:
    Jul 15, 2021
    25
    6
    0
    Location:
    Dalton, Georgia
    Vehicle:
    2010 Prius
    Model:
    V
    Nope... It was still in ECO mode, and I have tried all modes and the resistance/charging is there no mater what driving mode or gear i put the car in, except neutral or reverse, in neutral the car rolls freely with ZERO resistance or charge.
     
    #28 Tim Jenkins, Jul 17, 2021
    jerrymildred likes this.
  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,693
    39,238
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Brakes may be a red herring; does it really drop to 1 bar sometimes?
     
    #29 Mendel Leisk, Jul 17, 2021
  10. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,166
    50,060
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    he doesn't mean the battery icon, not sure what he is counting as bars
     
    #30 bisco, Jul 17, 2021
    Mendel Leisk likes this.
  11. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,166
    50,060
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    no, just make sure you put it in D
     
    #31 bisco, Jul 17, 2021
    Mendel Leisk likes this.
  12. Tim Jenkins

    Tim Jenkins New Member

    Joined:
    Jul 15, 2021
    25
    6
    0
    Location:
    Dalton, Georgia
    Vehicle:
    2010 Prius
    Model:
    V
    It will be obvious when I get my videos posted, sorry if I am not being clear in my descriptions
     
    #32 Tim Jenkins, Jul 17, 2021
    Mendel Leisk and bisco like this.
  13. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,166
    50,060
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    we await with anticipation!
     
    #33 bisco, Jul 17, 2021
    Mendel Leisk likes this.
  14. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,518
    14,128
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    I have never managed to directly put a video on this forum. But if you have a Google account (who doesn't these days?), you can put it there and post a link here.
     
    #34 jerrymildred, Jul 17, 2021
  15. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,915
    16,216
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Have you tried in the Media section?

    I haven't, but the "Upload a Video" tab in the Add Media page looks promising. Its "more info" display shows avi, m4v, mov, mp4, ogg, webm, wmv as accepted file types.
     
    #35 ChapmanF, Jul 17, 2021
    jerrymildred likes this.
  16. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,518
    14,128
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    Never messed with it. Sounds like a good idea. Thanks.
     
    #36 jerrymildred, Jul 17, 2021
  17. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,174
    4,079
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    :rolleyes:
     
    #37 Grit, Jul 17, 2021
  18. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,693
    39,238
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Try the test in the video I link (in post #7), to verify rear brakes not dragging, after brake work.
     
    #38 Mendel Leisk, Jul 17, 2021
  19. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,174
    4,079
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    :whistle:
     
    #39 Grit, Jul 17, 2021
    Mendel Leisk likes this.
  20. Tim Jenkins

    Tim Jenkins New Member

    Joined:
    Jul 15, 2021
    25
    6
    0
    Location:
    Dalton, Georgia
    Vehicle:
    2010 Prius
    Model:
    V
    Let's see if this works.
    1st Link is: Level road, coasting, ECO mode, shifting between Drive, Neutral and 'B' mode to show regen brake system.
    2nd Link is: 1/4 mile downhill, ECO mode, coasting in Drive
    3rd Link is : same 1/4 mile downhill, ECO mode, coasting in Neutral







    Thanks, Tim.
     
    #40 Tim Jenkins, Jul 18, 2021
(You must log in or sign up to post here.)
Page 2 of 5