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101k now / Never done any maintenence, now i'm getting poor mpg. What do I do?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by 240sxer, Apr 5, 2010.

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  1. patsparks

    patsparks An Aussie perspective

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    Your local Toyota dealer, insist on genuine parts and keep the feeling.
     
    #21 patsparks, Apr 10, 2010
  2. triumph1

    triumph1 Member

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    +1 here on the Redline D6. 13k miles, runs fine. My cars don't see the dealer either, unless it is a warranty issue, or something goes wrong above my skill level and tools.
     
    #22 triumph1, Apr 10, 2010
  3. 240sxer

    240sxer New Member

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    Ok, I replaced the battery with the Optima, I then drove about 40 miles, it was at 38mpg no change. So I changed the spark plugs with the Denso Iridium, I drove about 12 miles with that. It's at 39-40mpg, so no change again. I checked the tire pressure and it was at 36psi, so I brought them up to 44psi (I used to run them that high anyway), I know tire pressure isn't the problem I just prefer them harder for better mpg.

    I'm not sure where I should go now. I'll change the trans fluid and the coolants, but clearly those aren't the problem. What else might it be?

    The problem does not seem to be a MAJOR problem, I used to get around 44-46mpg in these same conditions, so it's about 6mpg down or so. What would be the next step?
     
    #23 240sxer, Apr 10, 2010
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Raise up rear axle and spin rear wheels to see if the parking brake is dragging, when the brake is released.

    2. Clean the throttle body, throttle plate, and MAF sensor.

    3. Have the wheel alignment checked and make toe-in as close to zero as possible.
     
    #24 Patrick Wong, Apr 10, 2010
  5. statultra

    statultra uber-Senior Member

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    whats typically the range you see your HV battery on the MFD?
     
    #25 statultra, Apr 11, 2010
  6. XxDarkSidexX

    XxDarkSidexX New Member

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    I also wonder
     
    #26 XxDarkSidexX, Apr 11, 2010
  7. Bob64

    Bob64 Sapphire of the Blue Sky

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    blue, 2 bars below max is what you should see... Do you see any rapid shifts in the mfd battery charge? from pink to green in less then a minute?
     
    #27 Bob64, Apr 11, 2010
  8. 240sxer

    240sxer New Member

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    The battery level seems normal. I've looked at it more lately and it seems as it usually was. I cleaned the throttlebody and maf today, I only drove it on my standard 'test loop' and I averaged 43mpg, so it seems like it actually improved it. I filled it up so I'll see how it does this week with my wife driving it. But it DOES seem better for the first time after all the stuff I've done. So I believe a dirty MAF might have been the issue. But we'll see, I haven't gone enough miles to know for sure yet.


     
    #28 240sxer, Apr 11, 2010
  9. 240sxer

    240sxer New Member

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    Ehh.. I jumped the gun. My wife drove it to work this morning and it got 36mpg. :( Any other ideas?

    Does it have some sort of fuel filter or anything like that that's replaceable?
     
    #29 240sxer, Apr 12, 2010
  10. jayman

    jayman Senior Member

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    The fuel filter is in the tank. Not an easily replaceable item
     
    #30 jayman, Apr 12, 2010
  11. 240sxer

    240sxer New Member

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    Any other ideas? Anything I can test or replace or clean..
     
    #31 240sxer, Apr 12, 2010
  12. 2009Prius

    2009Prius A Wimpy DIYer

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    Have you checked the parking brakes as suggested by Patrick Wong in post #24?
     
    #32 2009Prius, Apr 12, 2010
  13. 240sxer

    240sxer New Member

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    Yeah, the parking brake is fine.. It's not dragging or anything. Nor does it feel like it's dragging. :(
     
    #33 240sxer, Apr 13, 2010
  14. jayman

    jayman Senior Member

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    Weird. After MAF, spark plugs, checking for dragging brake shoes, not sure where you can go from here. Except fuel quality
     
    #34 jayman, Apr 14, 2010
  15. 240sxer

    240sxer New Member

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    The oil is at the full line, that's where I always have filled it to. Should I try draining a bit out? That's the only other thing I can think of..
     
    #35 240sxer, Apr 14, 2010
  16. jayman

    jayman Senior Member

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    I used to always keep the oil fill level about halfway between the two dots. Not sure if draining/siphoning a bit will help, but it can't hurt
     
    #36 jayman, Apr 14, 2010
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Wheel alignment?
     
    #37 Patrick Wong, Apr 14, 2010
  18. 240sxer

    240sxer New Member

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    Yeah, I'll take it to get an alignment since I've never gotten one. I don't think that would have that large of an effect on MPG but it couldn't hurt anyway.

    I'll drain a bit of oil to get it below the line some more. I doubt that's the issue but it couldn't hurt.

    I'll let everyone know how these things go. Any other ideas? Thanks for help everyone!
     
    #38 240sxer, Apr 14, 2010
  19. jdenenberg

    jdenenberg EE Professor

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    First, If the alignment is off it can lower MPG a noticeable amount, as well as poor handling at speed and rapid tire wear.

    One thing you haven't said is "Make, model and size of your tires". This can also impact MPG.

    JeffD
     
    #39 jdenenberg, Apr 14, 2010
  20. 240sxer

    240sxer New Member

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    I changed the tires a good 20k miles ago. The mpg didn't drop till the last 2-3k miles. But they're the stock size, I believe there continental tires, which are also low rolling resistance. I haven't gotten any strange wear o the tires, but I'll align it because it needs one anyway so it won't hurt.
     
    #40 240sxer, Apr 14, 2010
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