New to me 2011 Prius why is it getting 35-37MPG!!!

Discussion in 'Gen 3 Prius Main Forum' started by MilkyWay, Jun 20, 2017.

  1. MilkyWay

    MilkyWay Member

    Joined:
    Feb 20, 2013
    173
    39
    23
    Location:
    MI
    Vehicle:
    2008 Prius
    Model:
    II
    What do you think of waiting until I am 1 quart low (probably 2000 miles or so from now) and dumping a bottle of lucas in it....driving a day or two....and then going to Toyota for oil change?
     
  2. jdonalds

    jdonalds Active Member

    Joined:
    Mar 13, 2008
    445
    128
    0
    Location:
    Redding, California USA
    Vehicle:
    2008 Prius
    Model:
    Two
    Our 2008 Prius normally got between 43 and 50 mpg. We sold it with 163K miles on it. Zero problems except...

    For two or three tanks of gas we got in the mid 30's mpg. This was when the car had about 130K miles on it. Of course I thought it was the traction battery but after several tests decided it was good. I determined the problem was with the ICE. On a whim I dumped a can of SeaFoam in the gas tank. The mpg jumped back into the normal 43-50 mpg range. My guess is dirty injectors.
     
    MilkyWay likes this.
  3. LostPaul

    LostPaul New Member

    Joined:
    Jul 4, 2017
    4
    0
    0
    Location:
    Dallas
    Vehicle:
    2010 Prius
    Model:
    II
    2010 Prius with 156K miles, I get 40-41 mpg with AC on full blast for 8 hours in 95+ degree Texas heat.
     
  4. Mendel Leisk

    Mendel Leisk Lapsed Cargo Cultist

    Joined:
    Oct 17, 2010
    20,362
    9,011
    80
    Location:
    Greater Vancouver, BC, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Just to confirm, and this is due to Toyota's insistence on fudging the numbers: is that displayed or calculated?
     
  5. MilkyWay

    MilkyWay Member

    Joined:
    Feb 20, 2013
    173
    39
    23
    Location:
    MI
    Vehicle:
    2008 Prius
    Model:
    II
    I use AC from the second I start car up to the second I shut it down! Usually full blast.

    This is displayed and calculated which are very close.

    I dumped a bottle of Lucas fuel injector cleaner into tank....I ordered Blue Devil fuel injector cleaner....and a few small bottles of Lucas injector cleaner....I'll use it on fill ups and see what happens.

    I ordered Bars Valve Seal Oil Consumption repair and will put that in oil.

    I also ordered a Toyota oil filter + Mobil One 0W20 Advanced Fuel Economy.

    Hoping to get to low 40s with these snake oils! The only brand I am impressed with is Blue Devil...Had a Civic that gushed oil and I poured a bottle of Blue Devil stop leak and it magically stopped the leak....That's why I am going to try their fuel injector cleaner.

    I know it is mostly snake oil but I don't think it harms anything
     
  6. Yippeekyaa

    Yippeekyaa Junior Member

    Joined:
    Mar 19, 2017
    42
    35
    0
    Location:
    North Carolina
    Vehicle:
    2011 Prius
    Model:
    Three
    Just did 640 miles yesterday, pulling my camper on the interstate. Cruise control set at 5 mph over speed limit, averaged 43.9. Ac on the entire time. This was in the southern heat too. If your only getting 35 something is wrong.
     
  7. MilkyWay

    MilkyWay Member

    Joined:
    Feb 20, 2013
    173
    39
    23
    Location:
    MI
    Vehicle:
    2008 Prius
    Model:
    II
    I got 45 yesterday for the first time on a 45 minute drive on freeway with cruise.....I put Lucas Fuel Injector cleaner in it....and will be adding more on later fill ups.

    I am hoping this next tank shows avg. of low 40s....

    Typically the first 5 or so fillups are around 38mpg
     
    Yippeekyaa and Mendel Leisk like this.
  8. Yippeekyaa

    Yippeekyaa Junior Member

    Joined:
    Mar 19, 2017
    42
    35
    0
    Location:
    North Carolina
    Vehicle:
    2011 Prius
    Model:
    Three
    Great news!!
     
  9. 04priusnow

    04priusnow Member

    Joined:
    Apr 30, 2013
    155
    21
    0
    Location:
    USA
    Vehicle:
    2010 Prius
    Model:
    II
    149k on my 2010 with 17" FRS wheels get between 47-50

    Pixel XL ?
     
  10. Robert Holt

    Robert Holt Senior Member

    Joined:
    Aug 3, 2013
    1,001
    482
    0
    Vehicle:
    2012 Prius
    Model:
    Three
    Tire pressures may be part of this Gordian Knot: my dealer always put tires back at the 35psi spec after an inspection , but that was with compressed, heated air of course, so by the next morning the tire pressures would be in the low 30s and mpgs were noticeably lower until I pumped them up again.
    Since you have significant oil consumption, good luck getting it down.
     
  11. MilkyWay

    MilkyWay Member

    Joined:
    Feb 20, 2013
    173
    39
    23
    Location:
    MI
    Vehicle:
    2008 Prius
    Model:
    II
    Sorry I have been a little busy and lazy and I have yet to check the pressure on the new tires and I have yet to check the health of the 12V but showing no obvious signs of it being weak.

    I am just under 2000 miles on this purchase. I have added some fuel injector cleaner into the gas tank and over the last 300 or so miles I am showing 38.5mpg on the dash but haven't filled up yet to calculate myself (but everytime I have done it I am within 0.6 of dash reading).

    Still running 5W30 but will be swapping it for 0W20 Advanced Fuel economy within the week.

    My brother said instead of dumping potions into the gas tank I could just replace the fuel injectors?? Assuming this was the main culprit...

    I am thinking, with having really bad mechanical abilities, that it is just a warn high mileage engine...On an acceleration from 0 to 40 miles per hour the dash bars are showing between 0 and 25mpg....Sometimes I look at the bars and I'm just like, "man, this thing is showing 10-15 mpg on take-off"....Once it gets going and I put cruise on I can get the bars to display just under 50 or just over depending on whether it is flat or a slightly down-sloping road....It's the acceleration that is just ridiculous.
     
  12. Lightning Racer

    Joined:
    Dec 16, 2015
    109
    87
    1
    Location:
    Anchorage, Alaska
    Vehicle:
    2010 Prius
    Model:
    IV
    There's nothing ridiculous about low instantaneous gas mileage during acceleration. Any car uses a lot more power to accelerate than to maintain speed. A good running Prius might be some percentage higher, but will be in that range unless you are hypermiling. I see low mpg during acceleration, but that gets averaged out overall, and I'm getting 56 mpg indicated (maybe 54-55 mpg actual) 300 miles into my current gas fill up. 169K miles on the odometer.
     
    MilkyWay likes this.
  13. MilkyWay

    MilkyWay Member

    Joined:
    Feb 20, 2013
    173
    39
    23
    Location:
    MI
    Vehicle:
    2008 Prius
    Model:
    II
  14. Jkan2001

    Jkan2001 Junior Member

    Joined:
    May 22, 2017
    71
    17
    0
    Location:
    Dallas TX
    Vehicle:
    2010 Prius
    Model:
    Four
    That is impressive. Have you cleaned out the EGR system, intake manifold, replaced the PCV or any other major maintenance that's not in the official Toyota maintenance schedule?
     
  15. Lightning Racer

    Joined:
    Dec 16, 2015
    109
    87
    1
    Location:
    Anchorage, Alaska
    Vehicle:
    2010 Prius
    Model:
    IV
    Yes, all maintenance is up to date, including complete EGR system cleaning to like-new condition, which is not in the official Toyota maintenance schedule. Did replace the PCV valve, though it seems OK, though passing a lot of oil and sludge. Have an oil catch can ordered and coming on a slow boat from China. I've been reading Priuschat since before I bought my Prius (to research reliability issues), so I know the potential issues and have taken care of everything mechanical (still need to get around to doing some paint correction).

    In doing research on this particular car before I bought it, I learned that at 149K miles, 1,000 miles before I bought the car, the Toyota owner's database shows that the previous owner complained about lack of power and 35 mpg, but the dealer didn't find anything wrong and didn't do anything. When I was trying to buy the car, it failed the smog check due to a check engine light, was taken to the dealer to be fixed (MAF sensor and vacuum purge valve). It then had another check engine light while the previous owner was driving it for a week to clear the readiness codes before taking it back to smog check, and the A/F sensor was replaced to fix that. I still went through with the purchase. Maybe those things brought the mileage back up to around normal from 35 mpg.

    Other things: Inverter failed at 128K miles under previous owner (enhanced warranty covered), so it has a new IPM (guts of the inverter) and shouldn't fail again. EGR valve was sticking and was replaced under another enhanced warranty at 158K miles. I did new spark plugs (twice... one was causing a misfire, so I replace them all with the Denso Twin Tip model last month). I have used only Top Tier gas since I learned about that, and have run Techron twice. Burns minimal oil, though I monitor at each gasoline fill up because it is a good practice: about 1/8 of a quart in the past 8k miles. Original 12V battery that is fine even though it drained it twice (leaving doors open for days and similar). It's it tip top shape, and I expect it to go 300K+ miles.

    My recent driving has also been pretty ideal for gas mileage. I use Trip Odometer A to monitor daily trips and Trip Odometer B to keep track of current tank. Right now, my driving is mostly slower speeds in town, which helps gas mileage if the trip isn't too short (at least 7 miles or so to potentially get up to the high 50s mpg). If I want to semi-hypermile, I can do a 20 mile round trip with several hours between going out and returning (2 cold starts) and get over 60 mpg (63.7 on dash the other day). Several days ago I did a longer drive that was mostly winding highway (cruise control 55 mph), and then the 7 miles uphill on a low speed gravel road. Round trip for that was 85 mile and 57 mpg on the dash.
     
    Jkan2001 and m.wynn like this.
  16. douglasjre

    douglasjre Member

    Joined:
    Sep 13, 2008
    107
    39
    0
    Location:
    Orlando, FL
    Vehicle:
    2010 Prius
    Model:
    ----USA----
    What's the brake orientation thing?
     
Loading...