Mileage down to 30.6 MPG!

Discussion in 'Prius v Fuel Economy' started by Sara Hennessy, May 13, 2014.

  1. Sara Hennessy

    Sara Hennessy New Member

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    My 2012 Prius v (lowercase v) has about 80,000 miles on it, my work commute is 180 miles round trip daily. I had been getting 40-44 for about the first 18 months of owning/driving the exact same commute. In February I noticed when I filled the tank that the range showed around 370, which seemed odd, it was always over 400. I started tracking my mileage and it declined quickly. By mid-March I was getting a range of 320-340 with each fill up, and calculating MPG of 29-31. The dealer has had the vehicle for over a month now and can't find "anything wrong with it". Ummm, the MPG has dropped about 30%, isn't that something wrong?

    Wondering if anyone else has had a similar experience, and if it was ever resolved. Suggestions?
     
  2. JC91006

    JC91006 Senior Member

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    When I changed my spark plugs, I got 7 more mpg on my 2006.
     
  3. rdgrimes

    rdgrimes Senior Member

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    There's an abundance of info on these forums about what to look for, suggest you take the time to search and read up.
    Tires/inflation, wrong oil, bad 12v batt and the list goes on. Often there's a combination of issues contributing.

    The dealer won't do anything unless the car is throwing an error code. Good luck getting any action from them.
     
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  4. Sara Hennessy

    Sara Hennessy New Member

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    I have spent much of the past several months reading through these forums. Thank you. My vehicle has brand new tires, always serviced at the dealer on schedule, and supposedly all of those issues were checked the first time I brought the car in with the complaint, well over a month ago.

    Most posts here are complaints of MPG dropping below 50 (mine was never there!) or to the low 40s.

    I was hoping someone may have had a drop as drastic as mine, and found some resolution.
     
  5. fuzzy1

    fuzzy1 Senior Member

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    Please give us more information about your situation, by answering as much of this questionnaire as you can:

    Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new

    We can reply to a few things from your information already. You seem to have noticed the drop during winter. MPG varies seasonally, and in most climate zones is lowest in winter. New tires will temporarily cause reduced MPG until the tires break in. But if the new tires are not an LRR model, they will never get the same MPG of the originals.
    Most of those are people driving the smaller and more efficient liftbacks and 'c' models. Your 'v' will always be lower.

    Your very long commute is likely run at high speed, which also cuts MPG. Here is an MPG vs Speed chart for the Liftback.

    But all these are not enough to explain the low MPG you are seeing now. So please fill out the questionnaire to provide us with more clues.
     
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  6. Sara Hennessy

    Sara Hennessy New Member

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    Thank you for the attempt to help, but the page would not allow me to copy and paste with answers. I'll try this way.

    Yes, I've read the thread, and all others like it.

    Manual calculation, confirmed by dealer, 30.6 MPG

    Expecting 40-45, because that is what I got for the first 18 months.

    Temps range through all four seasons, below zero to sometimes 100.

    I commute 180 miles round trip per day.

    Original battery, vehicle purchased in August of 2012. Don't know the answer to the second question, as the vehicle is at the dealership.

    Alignment was checked the first time I brought the vehicle in with the complaint.

    97% highway driving, average speed 75-78, not a lot of stop and go.

    Terrain flat very nice highway

    Tire pressure - no idea, again checked on the first trip to the dealer

    Oil - no idea, doubt it, all service done by dealer

    Previous car - 2007 Prius, but did not make the same commute, it was 90 miles round trip then, and got 45-50 MPG

    Southeastern Massachusetts

    Mostly cruise control, not hard braking, never in electric only.

    Whatever mode is the default, eco I think.

    Not really warming up, unless it's very cold in the winter

    Using D mode

    Since I noticed the problem I tried not to use heat or AC at all. Generally don't use it to excess.

    Were factory tires up until March, now BF Goodrich, not sure of the model, size that the car says it needs.

    NO changes.
     
  7. minkus

    minkus Active Member

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    Have you checked the traction battery vent? It could be blocked, or the filter/fan could be dirty.
     
  8. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I do not see any Low Rolling Resistance BF Goodrich tires in your size.
     
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  9. Sara Hennessy

    Sara Hennessy New Member

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    I'm not sure what that means. I purchased them from a tire center based on the size the dealer told me (and I think it's on the car too). The dealer checked everything out, including the new tires on my first visit for the problem. And the mileage dropped before I had those tires.
     
  10. ksstathead

    ksstathead Active Member

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    Main reason your mpg is on the low side to begin with is your high speed. A choice you are free to make.

    Main reasons for your drop in mpg: New, non-LRR tires and winter temps. Expect some recovery as tires wear in and as temps rise. Oil fill level and viscosity also possible factors.

    If you don't have your own tire pressure gauge, buy one, and own that issue. Some 18 year old at the dealer who thinks 22 psi is cool could be costing you. Absolute minimum you should ever run is placard pressure on the driver door jamb. MPG will increase as you raise that pressure up toward the maximum spec of the tire sidewall. Play with that pressure range to see what you prefer. Ride is harsher, noisier, and vibrations worse at higher pressure. In every other respect, sidewall pressure is better.

    Check the oil fill level. Each time you have the oil changed, check it again. Overfill is all too common. I suspect they could easily have used the wrong viscosity, even if they charged you extra for the good stuff (0W-20).
     
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  11. rdgrimes

    rdgrimes Senior Member

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    That's a red flag right there. The wrong tires could easily be costing you 3-6 MPG, and low pressure another 2-3.
    17" low profile tires are hard to come by, there's only a few that truly offer LRR benefits. Whether its worth it at this point to justify replacing them is an open question that only you can answer, but at the very least you should pump them up to ~40psi. You'll see an immediate gain in MPG.

    You replaced the tires around the same time that you noticed the drop in MPG.
     
  12. Sara Hennessy

    Sara Hennessy New Member

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    Thank you for the information. I truly appreciate it. However, all of the items brought up here, most often the tires, only account for a drop of 5-9 MPG. We are talking about 14+. And the tires were replaced after the drop in mileage, not before.
     
  13. fuzzy1

    fuzzy1 Senior Member

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    Are you keeping track of every tank, so that refill variations can be averaged out?
    Both extremes will cut MPG. So will any precipitation on the road, and any wind.


    Best mpg should occur with dry roads, and the warmest temperature where you don't need AC.
    12V battery problems are not likely on something this young. Many 2010 came with batteries from a bad batch, but this is uncommon
    Speed is clearly an issue, a GenIII Liftback will barely do 40 mpg at 78 mph under ideal conditions (dry road, no heat/AC). Your 'v' will be lower, and won't even match your 2007.

    Was you previous commute in the 2007 at the same speed?
    Tsk tsk tsk. You should periodically check both of these yourself, don't trust the dealer. They have a different agenda than you, and best MPG is not on their list of concerns.

    Check the tire pressure when it is morning cold. When highway warmed, it will be several pounds higher. If set when highway warm, it will end up too low.
    Default is Normal, not ECO. But that can't explain what you are seeing.
    Do get the model name, and verify the size.

    Here is a list commonly of preferred Low Rolling Resistance tires. Non-LRR tires will cost some mpg.

    Low Rolling Resistance replacement tires: Current List
     
  14. Sara Hennessy

    Sara Hennessy New Member

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  15. miscrms

    miscrms Plug Envious Member

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    Just looking at your timeline above, you had stated that in Feb your range was down from 400+ to 370. And that by mid-march it was down to 320-340. You also stated that you replaced the tires in March.

    Mileage will be down pretty significantly in winter, which would account for the first observed drop. My understanding was it was a pretty rough winter in the NE, and lots of folks (Prius and non-hybrid alike) took larger than usual hits to mpg. The tire change could very reasonably account for the second drop. 14+ mpg drop would be a lot for just the tires, but not that unreasonable for tires and winter combined. You should be seeing some recovery as the temps come back up, but probably only about half of it if non-LRR tires part of the problem.

    I know its tempting to believe that there must be something wrong with the Prius's "secret sauce" that must be causing this decrease, but the reality is its almost always something much more mundane. Even if there was some fluke degradation of the HV battery for example, it likely wouldn't even affect your mileage enough for you to notice. When the DOE did end-of-life testing on the original Gen 1 Prius, they found that even when losing 60+% of their battery capacity over time the vehicles were still operating within a few percent of their original mpg. The system just isn't that sensitive. Its not usually until its almost completely dead that you start to see the impact, at which point there are other symptoms.

    The things people are suggesting above are the things that owners have found over millions of hours of collective "testing" experience that actually do impact mileage significantly. The overwhelming likelihood is that some combinations of those things is causing the noted drop.
     
  16. rdgrimes

    rdgrimes Senior Member

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    As previously stated, your problem is likely a combination of factors. But tires and pressure are the most critical and account for the majority of your mileage drop. Believe it.
     
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  17. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Look at the average temperature for the months you consider normal and the average temps after the mileage drop. Any difference? And was there snow/slush on the ground during the drop?

    Has the mileage changed now that the weather is warmer? How much?

    Have you measured the tire pressures in the morning after parking overnight? What were they?

    Are you in an area where they reformulate the gas in the cold months? Does this affect your mileage?

    And lastly, comparing a v to a hatchback gets you maybe 8-12 MPG difference (at least my son gets that on his 3 year old hatch versus my 2 year old v).

    Hope you get back to what you consider acceptable.
     
  18. vskid3

    vskid3 Active Member

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    The regular, liftback Prius, would probably get 5-10MPG better than your v/wagon in any given driving condition. Not sure why they directed you towards the v, its biggest advantages are rear seat headroom and cargo space.

    Tires are where I would start checking, but your mileage loss seems a little too high for it to be just tires. Still, don't expect the dealer to put in the right pressure and don't expect it to stay at the right pressure between visits to the dealer.
     
  19. catgic

    catgic Mastr & Commandr Hybrid Guru

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    Sara Hennessy - Lacking more data specifics from you, about your particular personal driving style, I do not think anything jumps out from your reported “dropped about 30%... calculated MPG of 29-31,” which indicates there is anything mechanically-functionally wrong with your v(vee). Depending on the characteristics of the particular non-LRR tire with which you replaced the OEM LRR tires, and their inflation PSI levels, running on non-OEM tires is good for a 4-6 MPG (10%-15%) “Hit” over the OEM LRRs. Additionally, comparing the on-board HSD-computer computed “Tank Range,” as displayed on the MID, against the hand-performed Per Tank-Full MPG calculations performed at your gasoline tank fill-ups, is a bit of “Apples & Oranges” MPG/Fuel Economy Data.

    If you were/are looking for/expecting to see the same MPG-FE out of the larger-size, 1.8-Liter Powered mit HSD powering your v(vee) Station Wagon through a less fuel-efficiency friendly axle-ratio, as was delivered to you by your old iconic 1.5-Liter Power mit HSD GEN II/2G 2007 Sedan, you shall continue to be disappointed. If you were going for/pursuing High MPGs, you should have purchased the 2012 Prius c(cee) “ÜberFuel-Sipper,” which is powered by the same 1.5-Liter Power mit HSD hybrid propulsion system as the iconic GEN II/2G --- not the thirstier 2012 “Caddy In A Kimono” 1.8-Liter Powered mit HSD v(vee).

    The Monroney Sticker on the 2012 v(vee) disclosed an EPA MPG of 44/42/40, and on the c(cee) it displayed an EPA MPG of 53/50/46, which shows that the c(cee) is typically 19% more fuel efficient.

    QUESTIONS:

    >> Is your driving style “Hybrid $mart,” or do you drive using a “Gas-To-Go/Brake-To-Stop” driving style?
    >> Are you running in Normal, or with ECO or PWR (default Drive Mode is Normal, not ECO) selected as the Drive Mode?
    >> Why did you leave your v(vee), which was still operating and drivable, at the dealer for a whole month, and what was the dealer doing to/with it to have to keep it there for a whole month?

    As a comparative data point of one, me and my 2012 v(vee) Five [same Five Level as yours] --- my 2012 “V”onder “V”agon displays an HSD-computer calculated Lifetime Average MPG of 53.1. I drive "Hybrid $mart," run with my original OEM Toyo Proxes A20 P215/50R17s tires Up-Pressured to MAX “COLD” SIDEWALL PSI [51F/50R], and operate in ECO Mode staying in the “GREEN ZONE” 99% of the time. My Range XXX Miles + Trip A/B XXX.X Miles usually sum up to 540-570 miles, with this number occasionally summing up to 600-miles. I travel at cruise speeds not exceeding 70 MPH. I usually cruise at the 66 MPH "$weet $pot" when traveling on the Highway/Open-Road/Interstate.

    IMHO, your "97% highway driving, @ average speed 75-78 MPH" is a key contributor to you falling short of the EPA 40 MPG-FE "Highway." FWIW FYI: When I cruise on the Interstate/Open-Road in my v(vee) Five at an electronic cruise controlled set speed of 66-70'ish MPH, over the 200-miles I-95 Interstate run from here on the Space Coast-To-Jacksonville, FL, I typically have 46-48 MPG-FE average fuel economies displayed on the instrument panel readout at the end of those 200-miles.
     
  20. DrElectron

    DrElectron Junior Member

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    Have the dealer check mass air flow (MAF) sensor and wheel bearing or brake drag.
     
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