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Old 01-20-2007, 12:14 AM
82Laredo's Avatar
82Laredo 82Laredo is offline
Join Date: Dec 24, 2006
Location: DFW
Posts: 218
How many miles should it go?

I've filled up 3 times since owning this thing and never gotten even close to 200 miles per tank. Is this normal? I've driven 120 miles in 3/4 of a tank and it's getting me upset.
I drive an average of 60mph and 40mph (on street). I don't take offf fast or hot rod. What can I do to improve this?
1982 Cherokee "Money Pit" W/T GONE
2006 Subaru Impreza AWD(wifes DD)
1986 Civic Si DD
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Old 01-20-2007, 12:31 AM
Duke(Gwag)'s Avatar
Duke(Gwag) Duke(Gwag) is offline
Join Date: Jan 14, 2007
Location: Washington
Posts: 107
you have a 20 gal tank with 9-11 miles to the gal. that sounds about right. She sucks gas and farts fumes what more do ya want.. i got a new air cleaner and got better gas mileage. but there are screws in the front of the carb(phillips) and you tight'n them until they are flush with the carb(dont overtigh'n only until they tuch the carb.) then back them out two full turns. this will put the fuel flow throught the carb back to normal if the carb was letting in too much gas. the air cleaner for me helped because i was burining to rich and the extra air helped balance that.

Last edited by Duke(Gwag) : 01-20-2007 at 12:36 AM.
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Old 01-20-2007, 12:32 AM
Don S's Avatar
Don S Don S is offline
Gone,But not Forgotten.
Join Date: Feb 06, 2002
Location: Burleson TX
Posts: 5,613

... How do you know when the tank gets to ¾ full? I don’t even trust the fuel gauges on new cars.

Read my article below.. Maybe it will help.

Boosting Fuel Mileage update 01.02.07
... It takes X amount of power to move gasoline engine vehicles from point to point. The engine converts gasoline to heat as the power source. Much more than fifty percent of the heat is wasted unused and is dissipated though the radiator and exhaust system. Large cubic displacement engines normally consume more fuel than smaller engines but this is not a ‘hard’ fact..

... Here is a list of a few of the mechanical things that can effect fuel mileage.

Cam and ignition timing, cam lift, duration and valve size. Leaky fuel delivery systems with vented vapor losses, restricted air induction systems i.e. dirty filters. Intake air can also be too hot or cold. Restricted exhaust scavenging systems. Operating temperatures of fuel and engine. Carburetors with bad power valves, accelerator pumps and fouled choke systems. Carbon fouled injectors, sparkplugs, and piston rings. Type of transmission, automatics without lock-up converters and over-drives, gear ratios. The type of tires, tire size, the tire pressures and the wheel alignment. Example; Just think, is it possible that larger wider tires require less ‘toe in’ that could reduce drag and get better fuel mileage? But the larger wider tires cause increased air flow resistance. The vehicle speed, the load, the wind speed and direction. The list can continue on including the type and additive mix of the gasoline. Gasoline blends are changed continually by local area, altitude and season. These are changes in the volatility of the gasoline. Winter Gasoline will evaporate much faster in the summer temperatures and less octane is required at high altitudes.The driver knowledge and ability is the big factor for achieving the best fuel mileage if the vehicle is in proper condition.

Make sure the odometer in the vehicle is showing correct mileage. And MPG means miles per gallon NOT miles per 'tank full'
An example of the simple formula is 200 miles divided by 10 gallons = 20 MPG
Full tank amounts will vary due to air trapped in the tank but the MPG will average out in the long run.
Here are a few thoughts about saving fuel.
First thing a driver will notice when they start to conserve fuel is it will agitate other drivers around his vehicle. Please be considerate of other drivers who have no concept of your economy driving. The other drivers want to race to the next stoplight and remember, If they don’t get there quick enough they won’t get to stop! When the timing of stop lights is known then speeding up to make a green light can save a little.
1. Think about driving as an art while doing so. Stop rubber-necking, turn off the music, turn off the cell and drive.
2. Install a dash-mounted vacuum gauge and use it. As the fuel mileage drops the vacuum needle drops. Try to prevent the needle from dropping below five inches. Readings will change with altitude changes.
3. Drive as if you had a fresh egg taped on the accelerator AND brake pedals.
4. Apply accelerator and brake petals smoothly.
5. Reduce speed as much and as soon as possible. Speeds above 50 MPH eat into the pocketbook!
6. Scan far ahead of your vehicle for traffic control signals and things that will allow you to ‘get off the gas’ sooner so you don’t have to ‘hit’ the brakes as hard – later. The over use of brakes means fuel has been wasted.
7. Drive as if your afraid your brakes are in poor condition and you are trying to save them.
8. Purchase your fuel in the morning when it’s cool and keep the tank full.
9. Air you tires up when they are cold and on the plus side of the recommended pressure and check them often especially on cold days. switching to nitrogen in the tires might help fuel mileage. Soft tires eat fuel!
10. Small amounts of high quality low ash synthetic Out Board 2cycle oil in the fuel (less than ¼ Oz per gallon) will clean, lubricate and reduce friction. The low ash oil will help the following items for better fuel mileage and life; electric gyrator fuel pumps, carburetor/injector parts, spark plugs, valve stems, compression rings and EGR systems. One fouled spark plug can drop fuel consumption by 10 percent. One sticky fuel injector can drop fuel mileage by up to one third.
11. Air dams can enhance cooling and reduce aerodynamic drag. Reduce the amount of air getting under the truck because the underside of vehicles create much air turbulence and drag at highway speeds. Bug shields, sun visors, wind deflectors, large roof top racks and large outside mirrors will reduce fuel mileage. Small camper shells or bed covers on pick-ups seem to aid fuel mileage.
12. The effect of heavy loads is detrimental to fuel mileage and brake life.
13. Modifying a vehicle with lifts and large wide tires is detrimental to fuel mileage and brake life.
14. Cruise control may save fuel in ‘flatlands’ but may not be economical in hilly country.
15. In hilly country do not allow the down hill run to cause engine ‘braking’ i.e. slowing down the vehicle unnecessarily. Run your fastest speed at the bottom of a hill and the slowest at the top. ... Only use engine braking when the vehicle is going to gain excessive and unsafe speed that would have required a fair amount of regular brakes. Excessive downhill braking can cause many heat related problems. Among these are warped rotors, brake fade, boiling brake fluid, wearing out pads, over heating seals, bearings and lubricants.
... Down hill engine braking and downshifting for increased engine braking is not going to consume very much fuel because the throttle will be closed. Long downhill runs of five or more percent grades are a good time for downshift engine braking. Two miles of seven-percent grades with curves should be mandatory.
So in hilly country it's a case of the having to use more throttle to regain the speed you lost by allowing short periods of unnecessary engine braking.
16. Allow the engine to warm up and/or drive gently till it does. Cold engines can get poor fuel mileage.
17. Put the transmission in neutral or stop the engine when long waits in traffic are encountered I.e. train crossings and long red traffic lights.
18. Reduce the Air Conditioning and the electrical demands on the alternator. Alternators draw much horsepower and extra fuel so fancy lights and sound systems burn extra gasoline and bother other peoples eyes and ears.
19. Short shifting. If the automatic transmission is equipped with overdrive and/or lock-up torque converter learn at what speeds it changes gears/locks. Often one can get the transmission into overdrive and lock the converter sooner by backing off the accelerator pedal a little at the right time.
20. The use of WOT (Wide Open Throttle) to gain speed is wasting fuel.
21. Buying a fuel efficient DD is a good way to save fuel and cut mileage on your 4x4. Our '04 Sentra averages 35.5 on the highway!
22. Consolidate your trips. Do more errands per trip and reduce the number of trips. This doesn't increase mileage but can cut the use of fuel.
23. Hey!.. wake-up!! We are sorry we put you to sleep… do you have any other ideas?
Calculating fuel mileage is not an exact science but stating it by the tank full is being somewhat vague E.i. "I get 198 miles per tank full".
... Many vehicles have a problem getting the final (up to) two gallons of fuel in the tank including our Sentra, Frontier, FSJ and Grand Cherokee. Sometimes air bubbles are displacing fuel and sometimes not. A lot depends on how level the surface is near the pump.
... Your fuel mileage also depends on the accuracy of the odometer reading and all of it depends ontire pressure and size, speed and driver skill. All the above assumes that the truck is properly tuned and in good mechanical condition
The wife and I keep accurate mileage and fuel records and we check the accuracy of the odometers

Have a good one, and Carry on.. Don S..
Sold our 1976 Wagoneer 406, MC4300, TH400, QT, TruTrac, 2" lift, 31x10.50s, duel Optimas,
It’s took us over 161 Colorado Mountain Passes, 3 Jeep Jamboree USAs & 2 Ouray Invasions from 1985 to 2010
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Old 01-20-2007, 12:41 AM
Duke(Gwag)'s Avatar
Duke(Gwag) Duke(Gwag) is offline
Join Date: Jan 14, 2007
Location: Washington
Posts: 107
if my gauge is off its of byabout -1or-2 i say negitive because whe it says im below a 1/4 ill fill her up and it say i had 5 gallons in the tank. Ya Me it feel better when i feel like i save money.
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Old 01-20-2007, 12:52 AM
J10Mike's Avatar
J10Mike J10Mike is offline
Delightfully Incompetent
Join Date: Jun 04, 2003
Location: St. Louis, Mo. 63052
Posts: 5,811
You have to realize that you are driving a heavy vehicle with all the aerodynamics of a flying brick. It's a part of yesterday's technology when the price of gas was anywhere from .29 to .69 cents per gallon and everyone could afford it.
If the cost of gas is bringing you down, it may be time to look for something more economical and let your FSJ become a weekend project and or play toy.
My J10 is not my daily driver and is my perfect weekend play toy.
Former - 1982 J10 Sportside, 360, TFI, 727/208, J20 axles, D44HD/Detroit TruTrac, D60/Detroit Locker, D60 disk brake conversion, 4.10s, 5 inch Superlift, 35x12.5x16.5 BFGs on AR767 Wheels. Procomp Super Seats. MileMarker 9000 on Cliffhanger front bumper. Dozer II rear bumper. Rhino Grill conversion. NP208 floor shifter conversion.

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Old 01-20-2007, 12:59 AM
82Laredo's Avatar
82Laredo 82Laredo is offline
Join Date: Dec 24, 2006
Location: DFW
Posts: 218
When I drove my Dad's 1982 GM truck with 350/400trans 4.10 14 bolt and 33x12.5x16.5 tires I would get 250 miles at least, on the street. That's when I was younger and drove it like it wasn't mine. It had 2 20 gal gas tanks and I only used one.
1982 Cherokee "Money Pit" W/T GONE
2006 Subaru Impreza AWD(wifes DD)
1986 Civic Si DD
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Old 01-20-2007, 09:44 AM
GWChris GWChris is offline
Bleedin' Gasoline
Join Date: Jan 22, 2005
Posts: 1,798
20 gallon tank, so you don't want to use more than 19. 11mpg gets you to 209mi. If it's running right and you're on a highway cruise at 65mph, you might get 13 to 14mpg, depending on what gears you've got (my '89 could do that, but it had the highway gears) - so that would get you to 260mi.

On the other hand, the tank is long and skinny and the fuel guage is probably shot (they all are), so you won't be able to risk pushing it that far. There is a reason we keep a log book in the car, and mark it at every fill up. In practice we never push it past 180mi. It would be nice if it had a trip odometer.

That's all they do - if you want better cruising range, you'll need a bigger tank.
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Old 01-20-2007, 09:56 AM
scantar's Avatar
scantar scantar is offline
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Join Date: Jul 16, 2005
Location: OK Denver, dangit! :)
Posts: 4,296
Originally Posted by GWChris

That's all they do - if you want better cruising range, you'll need a bigger tank.

Or a different vehicle.
'76 Waggy, TH400, Quadratrac and a fourOH!one Sold

My other car is a Viner Pro wait, my other car is a Masi Speciale...nonono, my other car is a Bianchi 928SL
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Old 01-20-2007, 10:14 AM
jamsni jamsni is offline
Master Mechanic
Join Date: Jul 01, 2005
Location: Archdale, NC
Posts: 989
In comparison, I have a brother that has a suburban and he gets about the same mileage, but he has a 40 gal tank.

Do you want to drive farther, or take your whippin' at the pump more often?
1988 GW stock (work in progress)
2003 GC Laredo (family car)

Thought it would be simple, forgot it was a Jeep.
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Old 01-20-2007, 10:23 AM
91G-Dub's Avatar
91G-Dub 91G-Dub is offline
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Join Date: Aug 21, 2004
Location: Magnolia, South Jersey (the 51st state)
Posts: 2,702
I mostly put around town never getting over 35-40mph, mileage sucks because of it.
I average 9-10mpg.
Best I ever did was on a long interstate drive with cruise at 65mph and got around 14-15 mpg
91G-Dub = Bill Houston

1979/1980 J-10 Junkyard Dog 258 4 speed D44 front AMC 20 rear 3.31 Lincoln Locker Status Running
1991 Grand Wagoneer Gray Ghost (bone stock) STATUS Gone but not forgotten

"The tree of liberty must be refreshed from time to time, with the blood of patriots and tyrants.
It is its natural manure."

Thomas Jefferson
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