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Is 11.2 MPG average for 97' 80 series?

Discussion in '80-Series Tech' started by FJ55partsBoise, Dec 21, 2003.

  1. FJ55partsBoise

    FJ55partsBoise

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    I just drove my wife's cruiser for the first time since we bought it. She drives mostly in town. We took in on the freeway and I only got about 11.2 mpg (250 miles on a tank). That seems low. We do have the largest stock tires on it without a lift kit that would fit if that is a factor....

    If 11.2 mpg is low what should I check to get the mileage improved?

    1) Tune-up 2) Oxygen sensor? 3) ?

    Thanks
     
  2. Razor

    Razor

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    got 16.5 outa mine,,highway, dallas to detroit--->70-75 MPH

    new MICH LTX's------K&N Filter
     
  3. Beowulf

    Beowulf

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    FJ55partsBoise,
    A stock '97 FZJ80 will get around 12 +/- MPG in city driving and around 16 +/- MPG on the highway. That is with stock sized tyres.

    You say you have the largest "stock" tyres that will fit without a lift but that doesn't tell us much. The stock size tyres are approx 31" diameter. If yours are larger then the odometer will read a lower number of miles than you actually travelled; resulting in miscalculation in your MPG. You'll need to give us the actual tyre specs.

    A tune-up is a factor of total miles since your last tune. Plugs, rotor, and dizzy cap are about all you would do depending on the mileage. The are MIL codes that will signal you when it's time to replace the O2 sensors.

    -B-
     
  4. FJ55partsBoise

    FJ55partsBoise

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    Hi Beowolf-

    thanks for the help...OK I checked the tire size. They are 285 75 16. The tire shop told us that was as big as would fit on that truck. When they are shot I am going back to stock size tires.

    Last tune was around 75k, truck is now at 111k. I was planning on all fluid changes and a tune up in May 04. My wife drives 400 miles a month all in town. In May truck may have 115 -117k.

    What do you think on the mileage, tires or tune?
     
  5. wob

    wob

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    [quote author=FJ55partsBoise link=board=2;threadid=9075;start=msg78847#msg78847 date=1072062575]
    Hi Beowolf-

    thanks for the help...OK I checked the tire size. They are 285 75 16.

    [/quote]

    You need to add 6% to your speedometer and odometer to compensate for that tire size. 50 mph on your dash = 53 mph actual. 100 miles on your odo = 106 actual, etc.
     
  6. Junk

    Junk

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    If you get 11.2, then be happy. That's about twice what I get. :flipoff2:
     
  7. Pitbull

    Pitbull

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    I have a 95 and get 15 mpg around town. You need to check your mileage using Beowulf's information. You also need a tuneup based on mileage and you need to change all your fluids to synthetic. Base on the mileage I would change the wires on this tune-up and use OEM wires. JMHO You can wait until the spring no big deal.
     
  8. ParadiseCruiser

    ParadiseCruiser

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    FJ -

    The subject of mileage returns to this forum frequently, and many of the regulars around here have posted the variables (in seriousness and jest) that contribute to good (or bad) mileage.

    There was a long thread several months back that resulted in the following list:

    Gasoline octane
    Grade of gasoline (states vary...)
    Engine mods (S/C or not)
    Engine timing/tuning (recent [or not])
    Exhaust mods (mufflers/cats [or not])
    Driving speed
    Driving elevation (Denver or Death Valley?)
    Weather (headwinds, etc [or not])
    Weight of truck
    Windage accessories (viz., rack)
    Tools, spares, etc. on board (or not)
    Gearing
    Tire size
    Speedometer correction (or not)
    Tire composition (soft or hard)
    Tire pressure
    Lift (inre: windage)
    Air condx (on or off)
    “Power” switch (on or off [in later models])
    Number of passengers
    Windows (open or closed)
    Dog (head in or out the window)
    Size of driver’s foot
    Weight of driver’s boot
    Number of dead dragonflys spread-eagle on your headlight screens
    (this one really does me in on my mileage...)


    Having said all of that, I get about 13 mpg on mine in town...

    Cheers, R -
     
  9. Beowulf

    Beowulf

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    FJ55,

    >> 400 miles a month all in town. <<

    That's not much driving so a good Italian tune-up every so often wouldn't hurt. Run some fuel system cleaner next time you take the 80 for a trip. If it helps, use it on another tank. If you use something like the BK44 product you don't want to leave it in the tank for very long. The Lucas product got mixed reviews (search the archives) a few weeks ago but it's worth a try. My dealer (Cruiserdan) stocks the BK44 product so that is what I use.

    Wob has the correct calculations for your tyre size. You and your wife need to be aware of this difference as it affects the speedometer.

    I agree with Pit that the synthetics will improve your mileage if you don't already use them. You can check the resistance of the plug wires and replace them if they are out of spec. Plugs should be replaced routinely (60k miles ? ) and that may improve your mileage.

    The bottom line is that you should be around 16 MPG highway with a properly running stock '97. (Assuming you're talking about 70 MPH speeds... not Junk speed.)

    -B-
     
  10. cruiserman

    cruiserman

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    In my experience, lifting the rig and adding larger tires have the most negative effect on fuel mileage. My rig got 15 to 17MPG in stock form back in '98. It gets ~12MPG now, before and after rebuild.

    For best mileage, run street tires in stock size, keep suspension stock height, and keep your foot off the skinny pedal.
     
  11. e9999

    e9999 You want to do what...? Moderator

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    on the '03 with Nav sys there is a real time mpg indicator. Pretty scary to watch. Some tantalizing clues that there may well be a soft spot somewhere around 60/65, though, but not sure yet. Interestingly, one might assume that low city speeds mean high mpg but not necessarily true apparently.
    E
    note: leisurely city driving with short stretches of highway gives so far about 13.5mpg, mostly freeway gives 15.5mpg with the :cheers:V8. This with 87oct
     
  12. krich97

    krich97

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    FWIW I get less than I anticipated too :-\ - about 12-12.5 (275 tires, no pwr or much o/d off) normally intown but that measurement (done twice now) includes 65% or more mileage on hwy. I have just done a complete (=60k) service, cleaned out injectors, and gone to synthetic in crankcase. I did not notice a big improvement in mileage - however I still stomp on the pedal here and there as I have had the truck less than 2 months and am still getting used to it (playing with it :D). I will try to take the measurement again with less heavy footed driving.
     
  13. cruiserman

    cruiserman

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    I didn't see any mileage benefit going with synthetic in my 80. I did notice a 2-3MPG benefit with my '94 toy 4x4.
     
  14. Beowulf

    Beowulf

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    We've had several discussions on improving the gas mileage. Your city average is typical. Do an archive search if you're really in to improving your mileage.

    Here are a few of the suggestions that I remember from prior posts:
    1. Check air pressure in the tyres (40 psi)
    2. Clean fuel system
    3. Flow test injectors
    4. Complete tune (plugs, rotor, cap, wires, etc.)
    5. Timing at 6 BTDC
    6. Good grade of petrol
    7. Fresh synthetics everywhere, not just the crankcase.
    8. Repack wheel bearings with syn and make sure they are adjusted properly
    9. New air filter
    10. No vacuum leaks anywhere
    11. Drive like an old grandma; avoid the skinny pedal.
    12. New fuel filter
    13. Proper belt tension
    14. Adjust valves if necessary
    15. New PCV valve
    16. Remove unneeded crap from the cargo area.
    17. Clean the intake with carb cleaner. Clean it really well.

    That should get you about all you're gonna get.

    -B-
     
  15. sjcruiser

    sjcruiser

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    I've got 17MPG from San Jose to Orange County, CA with approx. 1200lbs payload (including that 13 cubic inch cargo carrier storage on top). Same MPG on reverse direction. Maintenances are up to date & all fluids are synthetics (M1).

    Frank.
     
  16. cruiser101101

    cruiser101101

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    I'm getting on average around 13mpg around town in my stock vehicle with 275 tyres, I Haven't had it long so I've yet to calculate a long run.
     
  17. Asiarider

    Asiarider

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    Why do you care so much about the mileage ???

    I thought that petrol is cheap in the USA !!!!

    How much is 1 L now ???

    Mike
     
  18. MoJ

    MoJ Moderator

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    With 32 inch tires I get 14 mpg pretty much city or highway. Of course I have an ultra-efficient power plant, some of you may know it as a "3FE."
     
  19. cruiserman

    cruiserman

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    [quote author=Asiarider link=board=2;threadid=9075;start=msg79166#msg79166 date=1072125934]
    Why do you care so much about the mileage ???

    I thought that petrol is cheap in the USA !!!!

    How much is 1 L now ???

    Mike
    [/quote]

    You have to go up north (GWN) to buy gasoline in liters. National average is ~US$1.48 per gallon of regular gas.
     
  20. MTNRAT

    MTNRAT

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    Mike, a us gallon is about 3.78 litres.
    Sean