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2009 Prius - getting 28 MPG

Discussion in 'Gen 2 Prius Fuel Economy' started by Stephenjn, Dec 28, 2017.

  1. Stephenjn

    Stephenjn New Member

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    I need help. I have been reading the other fuel mileage threads, but am lost. I purchased a 2009 Prius about 8 months ago (third owner) for use as my primary vehicle, and to be used on paper routes I throw. I was averaging about 33-38 mpg, which I thought was lousy, but so much better than my previous non-hybrid. I put the mileage off to the paper routes. I fueled my car at Chevron, or Costco, because they had gas additives. When I did not, I got the lower gas mileage. I have recently started suffering mpg. I had the spark plugs and air filters (engine and cabin) changed, and used a fuel cleaner additive to clean the fuel system. No effect. I then did a "recommended" throttle bottle cleaning at the dealership. Still getting horrendous mileage. 26-28 MPG. One thing I think might be affecting it is the touch pad display is working intermittently on my car, and I struggle to get it off of A/C, though it is off 90% of the time. I have never had a hybrid before, so do not know what to do next. Suggestions? Prayers?
     
  2. bisco

    bisco cookie crumbler

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    cold weather (assume that's boise) and winter gas formulation are natural mpg killers, up to 20%.

    what are you setting the heat at? not sure what you mean by a/c, it's december.

    pump your tires up to 42f/40r and keep an eye on them.

    check your oil level, and air and cabin filters.
     
  3. Stephenjn

    Stephenjn New Member

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    Thanks for responding. Oil level is perfect and recently changed, air filters are brand new. A/C is air conditioning. (Sorry). I have my Auto Air Conditioning off, Air Conditioning off, and the heater on full blast on defrost. I set my tires to 40 psi, and have checked them. Also went in for a rotation and had the shop verify psi. I track my mpg with an app called Fuel Buddy, and on December 3rd (in Boise, Idaho) registered 29.93 mpg. I had a couple of fill ups run me in the low to mid 30's, then hit 27.77 mpg on 13 Dec. That's when I had the spark plugs and air filters changed. A week later was the Throttle Body maintenance at the dealership. I hit a low of 26.66 mpg on 19 Dec, then 33.15 on 22 Dec, then 28.52 on the 27th. I am all over the place on MPG, but feel there is NO WAY I should be in the 20's. Or am I wrong? I am a newbie....
     
  4. CraigM

    CraigM Active Member

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    I’m not familiar with all the different versions of the Prius, but the defroster might be causing the gas engine to run full time?
     
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  5. Stephenjn

    Stephenjn New Member

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    That made me do a Google..... apparently the defroster "may" use the same compressor as the air conditioner, but I need to do further research on it. A good direction to run in.... thanks.
     
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  6. jaqueh

    jaqueh Active Member

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    You may need a new 12V battery. Also this is in the wrong forum.
     
  7. bisco

    bisco cookie crumbler

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    yes, it might come on to dehumidify. 20's is a bit low, even for winter. tell us about your paper route; miles, starts and stops, average speed, etc.
     
  8. bisco

    bisco cookie crumbler

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    how many miles on her?
     
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  9. jaqueh

    jaqueh Active Member

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    Check out this entire page.
     
  10. Stephenjn

    Stephenjn New Member

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    Is was the forum it put me in (see "New member"... LOL) Can you assist me/tell me how to move it to the proper forum?
     
  11. Stephenjn

    Stephenjn New Member

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    I have been. I appreciate the suggestion.
     
  12. bisco

    bisco cookie crumbler

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    click on the report button on your original post and ask the mods to move it.
     
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  13. jaqueh

    jaqueh Active Member

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    Ah ok. Well usually the culprits are tire pressure, tire type, 12V battery, or main traction battery. Also weather and fuel blend, but I usually don't buy those arguments for such poor mileage.

    Also, how do you drive? If you brake very suddenly, you will get very poor mileage. Make sure you look up pulse and glide. That might dramatically improve your MPG without making you any slower of a driver.
     
  14. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    It is likely cold in Boise in December.

    December Weather for Boise, ID | Weather Underground

    Hints of days where the high was 23 F and the low was 8 F.

    Your Prius will not get as good of gas mileage when cold as when it is 80 F.

    1) All cars do worse in cold weather, oil and lubricaticants are thicker, roads are slipperier,air is denser, etc.

    2) All cars do worse when they are cold, they are programmed to run richer, they need to warm up to get better emissions, the driver runs more heater, etc.

    3) A Prius in particular does worse in cold, it turns off less at idle to keep heat to the driver, it runs the engine longer to get good emissions, Battery chemistry changes with tempurature, you are more likely to have headlights on, etc.

    What can you do to combat cold? Engine Block heater, cover radiator grill, heated garage, move south, etc.

    Engine Block Heater for 2004-2009 Toyota Prius - PriusChat Shop
     
  15. bisco

    bisco cookie crumbler

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    see post #2.
     
  16. jaqueh

    jaqueh Active Member

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    Cold weather wouldn't make it go to 25mpg though. I really do think it's the 12V.
     
  17. Stephenjn

    Stephenjn New Member

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    124,350 miles. My paper routes total about 32 miles. Constant stopping and starting, with plenty of u-turns thrown in. Average speed about 10-15 mph. I throw 245 papers, so consider that about 225 stops and starts in a three hour period.
     
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  18. bisco

    bisco cookie crumbler

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    getting a car moving from a stop uses the most amount of energy. that can be a big mpg factor.
     
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  19. jaqueh

    jaqueh Active Member

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    Try starting and braking much more smoothly than you're currently doing. Check this out.

    When my family first got our '07, we drove it like we would any other car. That is wrong. With the older Prius, make sure you adjust your driving style and especially learn how to tell when the friction brakes make contact so you can prolong regen braking.
     
  20. bisco

    bisco cookie crumbler

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    a good test is to reset the meter, and take it on a long drive under varied condones and see what mpg's she returns.
     
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