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Engine braking in D mode

Discussion in 'Gen 2 Prius Main Forum' started by Lightcycle, Aug 1, 2015.

  1. Lightcycle

    Lightcycle Junior Member

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    it seems to me my Prius 2007 decelerates noticeably when I take my foot off the accelerator. It's noticeable but not even near the level of the engine braking in B mode. The change seems to have happened since my last service but the I won't swear to it, and the dealer says there hasn't been a software change.

    The dealer is a trustworthy Toyota dealer. They suggested maybe an injector cleaning could help, but he admitted it was just a guess. Before I pop for this $100-odd dollar procedure, I wanted to know if anyone else has noticed greater deceleration this summer (2015), coupled with slightly worse fuel efficiency. The dash display reports I'm down 10mpg from my usual summer MPG of high 50s.
     
  2. bisco

    bisco cookie crumbler

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    welcome! that's correct. if you don't want regen, you have to apply the accelerator pedal very lightly. use the energy screen to see no flow of power from the motor to the battery.

    measure your mpg's by the tank fill up, not average running. even better, by several tanks averaged together. if you still find that your down, fill out the sticky, 'why am i getting lower mpg's'? then we can help diagnose the problems.

    some areas you can check before paying the dealer would be 12 volt battery, tyres pressure, throttle body and mad sensor, spark plugs, air and cabin filters, oil level.

    how many miles on her?
     
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I notice stronger Engine braking in D when I have Cruise Control on and I am traveling faster than the set amount.
    Coasting from the same speed without CC has weaker engine braking.
     
  4. Lightcycle

    Lightcycle Junior Member

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    Just finished with the dealer. One thing they just fixed was the front bumper and splash shield. Due to the struts needing replacement (I just found out) it had been dragging a bit in the wheel well. This could definitely have caused this slow down. I'm hard of hearing so it's possible I hadn't heard any new noises. I had noticed the bottoming out on big bumps. I need to see how it drives now, and get the struts fixed before I worry more about the feeling of drag.

    That's interesting, Jimbo. Though this is a change and I don't think I've changed that behavior, I'll have to experiment a bit around the cruise control as well. That's easy enough to try any time.

    Bisco, thanks. I think I'm saying the regen is stronger than it used to be, not that I don't want it. The change is recent and feels somewhat sudden, and that would fit with the splash shield damage. Of course we can't judge our real MPG from the display. I was only using it as an observation of a change in relative efficiency. I have been judging over multiple tanks, too. I know summer fuel formulations offer better mileage, so I've adjusted for that too. The real measure for me is the feeling of stronger than usual regen with no feet on pedals.

    This lightcycle has been run on the game grid for 182,000 miles. I'm just starting to think about replacing the buggy. The estimated repair bill is non-trivial.
     
  5. bisco

    bisco cookie crumbler

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    you may want to jack it up and make sure all the wheels are spinning freely.