Reduced Range on Full Tank

Discussion in 'Prius v Fuel Economy' started by kylexchang, Apr 22, 2020.

  1. kylexchang

    kylexchang New Member

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    I started noticing a reduction in range on a full tank of gas on our 2012 Prius V. When we first bought the car it consistently got 440+ miles per full tank. Now that the car has gotten older, in the past 2 years I've seen a significant drop. After each fill up I noticed that the range on the display never goes pass 375 now. Is this due to the age of the vehicle? Anyone else experience this?
     
  2. bisco

    bisco cookie crumbler

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    possibly. the thing is, to get a better handle on it, you need to start tracking mpg/tank every time you fill up.

    if you haven't done in the past, you have nothing to compare it to though.

    how many miles on her? there are a lot of things in an 8 year old prius that affect mpg's. in fact, there aren't many things that don't.
     
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  3. Ronald Doles

    Ronald Doles Active Member

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    You didn't state the mileage but with an 8 year old vehicle, it may be that the traction battery is starting to lose some of it's capacity which would force the gas engine to run a bit more.
     
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  4. Air_Boss

    Air_Boss Senior Member

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    DTE is calculated based on recent average MPG, so a reduced DTE on fill indicates either a recent lower average MPG or a short fill.
     
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  5. kylexchang

    kylexchang New Member

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    Thanks guys. My 2012 Prius has approximately 117K. I will start tracking tank by tank but I do know for sure that it has gone down significantly, even if I'm babying the hell out of it, i.e. no AC, try not to come to complete stop at lights, try to keep it in EV mode as much as possible. I'll track the next few tanks and get back with results.
     
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  6. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Has the EGR system ever been cleaned? Yours is at the miles they frequently give trouble. This ultimately affects the air/fuel mixture which is a key component in MPG.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Also, has the nature of your driving changed? Are you doing more short trips for example? That'll knock down the efficiency.
     
  8. tvpierce

    tvpierce Senior Member

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    Welcome!

    FYI, keeping it in EV mode as much as possible is not helping your long-term MPG. It will give you a short term spike because the ICE (internal combustion engine) is not running for a while. But that battery will need to be recharged... and when you think about it, all energy in a Prius ultimately comes from the ICE.

    It's a different equasion with a plug-in hybrid because some of the battery charge comes from the electric grid. But in a standard hybrid, the ICE is the sole source of energy.
     
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  9. RAM v

    RAM v Junior Member

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    Some of the (recharging) energy your Prius uses comes from regenerative braking. Planning of routes and maximizing regenerative braking definitely does help MPG for me.
     
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  10. tvpierce

    tvpierce Senior Member

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    The car was put into motion by the energy derived from the ICE. So the regenerative braking is just re-capturing some of that energy.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Never the less it's impressive, recouping energy that'd otherwise be lost. You can do this on a very simple level without the regen too: just keep a good following distance, try to avoid hitting the brakes, coast up to slowdowns.
     
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  12. tvpierce

    tvpierce Senior Member

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    No question, the car is brilliantly designed. When you try to force EV, you're working against the brilliantly designed software.
     
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah I don't "force" it, but I do keep keep an eye on the HSI bar display (Hybrid Synergy Indicator??): if I've got plenty of charge I'll try to keep the bar just to the left of median, keep it electric-only. Once the state of charge starts dropping signif. I'll knock off, revert to pulse and glide more.
     
  14. NuevoArchitect

    NuevoArchitect New Member

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    In September of 2019, I purchased a 2014 Prius V with 84K on it. The car salesman topped off my tank when he handed over the keys and the range reading said 475 with a full-tank. The station that we bought the gasoline at is "economical" and "guarantees" its fuel. On subsequent fill-ups, I used a different fuel chain with the "best" priced gas in town. The ranges started dropping. 450, 425, 415, 405, 395, 385, and then settled around 375 as the norm. This is not all that great for an 11.9 gallon tank.

    Making a long story short, I started using the chain from which the car dealer had gotten my first tank. I would drive the vehicle until the range was near zero or at zero for a few miles and then stop by one of these fuel centers that "guarantees" its gasoline. I noticed that as the tank reached empty the car would not "take-off" with the same power as on a fuller tank. It was rather sluggish. My assumption was the "poor" quality fuel has settled on the bottom of the tank. It might have been "stretched" with water which is heavier than gasoline. This is why the "fuel" was likely less expensive at the other provider.

    I also stopped by AutoZone and Advanced Auto and asked some questions. I was considering using a fuel additive product that I had used on my 1995 Toyota. It was called Berol B-12 Chemtool. It clears carbon and other pollutants from the fuel system. And, my Toyota dealer put a bottle in my tank each time I stopped in for a tune-up, after they changed the plugs and coil packs. But, the clerks recommended other products. I settled on SeaFoam for about $9.00 per bottle. I was told this was the best tune-up in a can on a price per value basis. However, the clerks each said the absolute "best" product for clearing out carbon was BG44K which cost $25.00 per bottle. However, one said the he used the Sea Foam in his vehicle. Using a can of Sea Foam additive on my last three tanks increased my range by 40 miles. It was 415 before adding it. Now, it is 455 without it. Simply, by changing fuel stations, over the course of five or so fill-ups the range had increase from a consistent 375 and reached the 415.

    Also, I am scheduled for a regular mechanical tune-up in four months. Hopefully, my Prius will break that 475 or 500 range barrier. I am not a mechanic and do not specifically endorse any particular product, fuel station or additive. Your results might be different in your area of the country.
     
  15. fuzzy1

    fuzzy1 Senior Member

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    That displayed range is not based on 11.9 gallons. A couple gallons are set aside as safety margin or reserve, and not counted when computing range.

    But MPG is far more useful than estimated range. What displayed MPGs are you seeing for each tank refill? Or better yet, what MPG are you calculating when filling up, if you do that calculation? (The displayed MPG is slightly "optimistic")
     
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  16. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd say a bit more than slightly optimistic, getting Into embarrassingly optimistic territory, lol. Very consistently so, too: by design?
     
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  17. tvpierce

    tvpierce Senior Member

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    The range/miles-to-empty display is a projection based on past performance.

    The MPG display is an projection based on the miles actually driven and an estimate by the ECU of the fuel delivered over that distance.

    Manually dividing the actual miles driven by the actual fuel consumed is the only way to calculate true MPG.
     
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  18. Mendel Leisk

    Mendel Leisk Senior Member

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    Some will argue that the vagaries of fill-up procedure (pump clicks off sooner or later) will skew mpg calc, but it's not by much. And: any "zig" in one calc, will be compensated by a "zag" in the next. Calculating multiple tanks, the numbers get inexorably more accurate.
     
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  19. tvpierce

    tvpierce Senior Member

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    Exactly!
     
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  20. Tim Jones

    Tim Jones Active Member

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    Have you ran a fuel system cleaner?
     
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