Poor Fuel Milage

Discussion in 'Gen 2 Prius Fuel Economy' started by Dbryant1732, Apr 9, 2018.

  1. bisco

    bisco cookie crumbler

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    but they wouldn't be the cause of the decline from 40 to 29, unless they were installed at that time.
     
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  2. MelonPrius

    MelonPrius Active Member

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    That's what I think. OP changed plugs, pvc, air filters, tires, and 12v. Nothing with the brakes. If anything, that should increase the overall mpg, not dramatically reduce it from ~40 to ~29 mpg. I keep thinking of a failing traction battery.
     
  3. bisco

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    also changed the tires after the fall in mpg.
     
  4. Dbryant1732

    Dbryant1732 New Member

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  5. bisco

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  6. Dbryant1732

    Dbryant1732 New Member

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    This is average for me driving interstate doing about 70 mph. For most the trip, I try to stay behind semis too to break the wind lol.

    Posted via the PriusChat mobile app.
     
  7. bisco

    bisco cookie crumbler

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    what did you calculate on your last fill up?
     
  8. The Electric Me

    The Electric Me Go Speed Go!

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    All I can have is suspicion.
    But I'm suspicious of it being something connected to the Hybrid Battery or the Hybrid Battery itself. With MPG loss at that level, that's where I'm drawn. Plus...

    That's a suspicious statement from a seller. Why would someone go to the financial investment of Hybrid Battery replacement and THEN sell vehicle? If you planned to sell it and was at all proud of the replacement, why wouldn't you keep receipts proving the work was done?

    There's a lot we don't know.
    Primarily...was it REALLY replaced?
    If so by who? If so with what? Remanufactured? Refurbished? Salvaged? OEM?
    Whole Battery or individual cells?

    Not knowing anything about this bit of history could mean nearly everything.

    But given how low your MPG actually is, I'm discounting factors like tires, highway driving speed, and PSI. Not that those cannot have impact to some degree but I don't think either separately or in concert, those factors shouldn't put your mileage in the mid to low 20's. My opinion on HSD is it's a amazingly durable system. It covers up for a multitude of drivers sins.

    I think you'd have to be using Fred Flintstone "stone" tires to get the mileage you are getting.

    It's pure speculation, but I'd be waiting for the inevitable Hybrid Battery Failure code.
    My dark and unfortunate bet, is going on HV battery related problem.

    I hope I'm wrong.
    Be nice if it was as simple as pumping your tires up, driving a little slower on the freeway and/or just replacing your 12 volt battery.
    But, given the sellers apparent statement, I can't muster up that optimism.

    Again, I hope I'm wrong, and if it makes you feel any better, I easily could be.
     
  9. Dbryant1732

    Dbryant1732 New Member

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    I was able to get a hold of the seller. He told me where he has been getting the car serviced at and where the battery was "replaced" at. I am going to try and get in contact with them and find out more about the car, hopefully they will provide me with more information. This is the third Prius the owner had, and had all the work done at the same shop, he said they know him well, and he never gets receipts, he just has them keep in on file. He said he wasn't planning on selling it, but his wife wanted a van to tote around their 3 kids, and not the 2 Pruis they had. I had the feeling it is the the HV battery, I am already getting prepared for that to go out. While driving, it doesn't really stay charged much, and when I am in traffic and it gets fulled charged...it is down to about 2-3 bars within about 5 mins, which I feel is not normal.
     
  10. Dbryant1732

    Dbryant1732 New Member

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    Last fill up, I calculated 28.6 MPG
     
  11. bisco

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  12. BlackBetty

    BlackBetty New Member

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  13. Dbryant1732

    Dbryant1732 New Member

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    the weather here lately has been extremely crazy. We had snow and freezing weather on Monday and Tuesday was in the 80's
     
  14. BlackBetty

    BlackBetty New Member

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    Kinda the same here in NC. Heat in the morning, AC in the afternoon, heat at night.
    We have 3 or four versions of all 4 seasons!
     
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  15. Erik Owens

    Erik Owens Member

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    Havent read but a few posts to start since people like to ramble nonsense but I would also look at your HV Battery state of charge. I dont want to worry you about your HV Battery but when that sucker gets corroded or state of charge is not where it needs to be it will hurt your MPG instead of the engine performance area. Take it to a specialty hybrid shop if you have one in the area or possible local dealership might be able to help you out. Reading State of Charge isnt difficult but the end game is what needs to happen to fix it which could be pricier than you could expect.
     
  16. sandy11246

    sandy11246 New Member

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    Didn't notice if anyone mentioned cleaning the MAF and throttle plate. Read through it fast so could have missed that mentioned. As some said 40-42psi front, 38-40 rear, 2 psi spread. Keep cruise @ or below 62 MPH if possible, and check ICE operating temp (180*-190*). Also, for the most part, drive the vehicle normally, except try to say away from jack rabbit starts. Try these actions and see if mileage improves. hope this helps Peace. Post results.
     
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  17. Dbryant1732

    Dbryant1732 New Member

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    I have not cleaned the MAF but it looked good to me when I was checking everything out. I did increase the front to 40 psi and rear to 38 psi. The ICE temp has been normal the few times I have checked it while driving. I do not hot rod the car or step on the gas or anything.I have had seen no improvements.
     
  18. BlackBetty

    BlackBetty New Member

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    [QUOTE="I try to stay behind semis too to break the wind lol.

    Posted via the PriusChat mobile app.[/QUOTE]
    Drafting, Lol! I made a trip your way West of Asheville. From the foothills to the mountains and back (200 miles or so) I averaged 50 mpg all hwy. Not bad since my 07 has 199k. I just got a new hybrid battery cell (#5 I think, idk). I’m getting about 42 city. I know a great place (NC) that works on them cheap, just saying.
     
  19. Prodigyplace

    Prodigyplace Senior Member

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    The only place to get one of those is from Toyota as part of a new battery pack. You can get used modules that may still have life though.
    The advice here is to generally either get a Toyota OEM battery pack or use @2k1Toaster's kit of new cells if DIY. The kit replaces all cells for $1600 shipped. The link is in my signature.
     
    #39 Prodigyplace, Apr 22, 2018 at 6:05 PM
    Last edited: Apr 22, 2018 at 6:35 PM
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  20. BlackBetty

    BlackBetty New Member

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    Whatever, he did it worked. It didn’t cost me that much.
     
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