deceleration, coasting/gliding not sure

Discussion in 'Gen 2 Prius Technical Discussion' started by Hugmac, Dec 5, 2011.

  1. Hugmac

    Hugmac New Member

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    New to the forum and did not notice any posts relevant to my problem.
    #Me: have driven Priuses off and on for years (fleet), but not much over the past few years.
    #Car: Just got one from the fleet for my own (2005) in August 2011. Has been great, I had even driven this particular car when it was new to the fleet.
    #Recent Maintenance: had the oil changed about 400 miles ago.
    #Problem: Now as I drive I notice that as I am coasting (I believe) the car decelerates more than I general notice, about 1 mph per second. This seems to happen even on slopes that I would consider more than slight. I have also noticed that the mileage has gone down somewhat... I know, 2-3 mpg loss only bothers a Prius owner, but while I could fairly easily get 52-53 on highway, I now have to work at 49 to 50.
    When I first noticed it, I tried pulling off the side of the road and putting it into the Engine-Breaking "B" mode on the shifter. (The drag/deceleration was not nearly so strong as the B mode.) When I shifted back into drive (on a rolling country road at this point), there seemed to be some positive effect, but after a couple hours at rest, got back on the highway and the same thing happened.
    #Hypothesis: If I am not imagining the problem, I am guessing that whatever is charging the battery as I coast is getting a little overzealous.
    #Questions:
    1. Am I more than likely imagining it?
    2. Has anyone imagined similar problems?
    3. Have said hallucinations been successfully treated by any psychosomatic therapy, e.g. watching a mechanic wave a wrench around behind one of the tires?
    4. What more should I look at to help assess the problem?
    5. How much can I drive with the perceived problem before I wreck the energy recovery or something even more important?
    6. Anyone have any other thoughts or suggestions?
     
  2. F8L

    F8L Protecting Habitat & AG Lands

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    Are you simply lifting off the accelerator and coasting/regenerating or are you reapplying a little pressure on the accelerator to enter a glide (no regen)? If you are just coasting then of course the car will slow down faster than a glide.

    You may want to check your tires. Non- LRR tires can feel like they are dragging the car down.
    Low pressure can't cause the car to roll less easily as well. Sometimes people forget that as temperatures drop so does their tire pressure.
    Check the emergency brake to ensure it's not sticking.
     
  3. tv4fish

    tv4fish Member

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    Hugmac -- Just another "possiblity" -- Could any of your brake calipers be "hanging up" now --- ever so slightly and therefor creating the drag?
     
  4. efusco

    efusco Moderator Emeritus
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    Similar thoughts as tv4fish--would double check that the parking brake is completely disengaged--mash it to the floor then quickly step and release it. You may well be dragging those friction brakes.

    The other possiblity is that you're just not used to the preset degree of built in regen--it's supposed to simulate the amount of drag one would normally experience in a conventional automatic transmission vehicle..

    If you very slightly depress the accelerator--not enough to increase engine RPM at all--does that drag effect go away?
     
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