Topic: Gas Mileage Thread

[sharpxmen]

13 or 14 mpg (never better) city and/or highway (with all she's got - top speed is 85mph with favorable wind conditions ). Rarely use 5th gear (only downhill otherwise it slows down...)

95 YJ / 2.5L MPFI
 - transmission: stock AX-5, stock diffs (4.10 if i'm not mistaking), stock t-case
 - tires: 33x12.50x15 BFG M/T
 - 3'' lift + 1'' body
 - cold air, 4.0TB, spacer, high ouput alternator
 - no speedo calibration but measurements based on gps

[kidwithayj]

NV3550
2.5L
30X9.5 BFG AT
4.10
Speedometer Calibration [No]
4.0L Throttle Body, Rock-It intake, new exhaust

My mileage is not really consistent. I have 104,500 miles on the Jeep. When I first got it, it averaged about 17.5mpg no matter how I drove. Now that it's a bit older, my mileage can go anywhere from 13mpg to the highest ever of 19.7mpg (just a few weeks ago, actually). I would say my average is around 16mpg. I think the motor is losing compression, so that could account to less mileage.

[01amberfirewv]

01 TJ AX5 Stock 4.11's and 31" TrXus Mt's

*OK but what's your mileage?

[InFlames]

17mpg average city/highway mix


Transmision Type: AX-5 manual
Engine Type: AMC 2.5L
Tire Size: 33x12.5x15(Truxus M/T= heavy)
Differential Gearing 4.88
Speedometer Calibration: yes
List of ENGINE Mods if any: None
Notes: Run all synthetic fluids,aftermarket muffler added,run alloy rims
    Also live in ozark mountain area so constantly deal with hills.

[larryp]

 About 18mpg since I lifted it and added larger tires.

tranny; AX-5 manual
engine; 2.5 liter tbi
 tires; 31x11.5x15 LT Wildcat AS
gears; 4.10
speedo cal.; no
mods; 2 1/2" low pressure exhaust and cat.

 As of today engine has 126,000 miles and uses no oil. Most of the miles are at highway speed as I live 16 miles from town and work.

[Jeffy]

Well, here's an update. I joined the 14-15mpg club.  I've run it this way for a few months to make sure it wasn't a fluke.  So tonight I swapped some stuff back and I'll be doing some more testing.  I have to say though, dropping form 16-18 mpg to 13-15 mpg makes a big difference for day to day driving.  I don't want to jump to conclusions so I'm holding off disclosing what is happening until I see if my mileage bounces back.

[jfrabat]

On my 94 YJ 2.5L with bout 117K miles, I get about 15 mpg (but my speedo was not calibrated; I just replaced it, but have not yet filled the tank up), mostly doing short drives combining both highway and city (it's about 10 miles to work).

Transmision Type: AX-5
Engine Type; AMC 2.5L MPFI
Tire Size: 31x10.5r15 BFG h/t
Differential Gearing: 4.10
Speedometer Calibration: No
Engine Mods: TB Spacer, Bosch injectors (Mustang), K&N Air Filter in stock box (restrictors removed), aluminum radiator with Ford Taurus fan with DC Control speed controller (and override ON and OFF switch, but mostly stays on Auto), Accel 42K Volts coil, no leaks.

Felipe

[spoonman]

i've put 3 tanks thru the jeep since tune up. crappy plugs ( and everything else) got 16 with no top. since the tune up, fuel system cleaner got 19 mpg around town and no top. it's a 97 stocker with 111000 on it.  is this good? i'll prolly drop a k&n 4.0 tbi and spacer next

[dexetr30]

16-19. Since swapping out the plugs/cap & rotor and adding the jet chip it's closer to 19. I still think I can do better. Maybe some sea foam and some injector cleaner.
 Prior to these mods I was just above 11 mpg.

[lanulos89]

im back from the dead with an update.  so i had my jeep in the air and noticed that the axle shafts never unlock from the driveshaft so its been spining constantly for god know how long since december when i swaped my axles out.  i hammered the fork back out of 4wd nd i get like 15 mpg now its amzing 

[jfrabat]

On my 94 YJ 2.5L with bout 117K miles, I get about 15 mpg (but my speedo was not calibrated; I just replaced it, but have not yet filled the tank up), mostly doing short drives combining both highway and city (it's about 10 miles to work).

Transmision Type: AX-5
Engine Type; AMC 2.5L MPFI
Tire Size: 31x10.5r15 BFG h/t
Differential Gearing: 4.10
Speedometer Calibration: No
Engine Mods: TB Spacer, Bosch injectors (Mustang), K&N Air Filter in stock box (restrictors removed), aluminum radiator with Ford Taurus fan with DC Control speed controller (and override ON and OFF switch, but mostly stays on Auto), Accel 42K Volts coil, no leaks.

Felipe

The new speedo has not done anything for gas mileage; it still is 15 mpg.  I do like knowing what speed I am driving at, though!

[Jeffy]

The new speedo has not done anything for gas mileage; it still is 15 mpg.  I do like knowing what speed I am driving at, though!

Since you have only 31's the difference is probably around 3% difference.  You should still see the mileage creep up a little with the calibrated speedometer/odometer.

[jfrabat]

Since you have only 31's the difference is probably around 3% difference.  You should still see the mileage creep up a little with the calibrated speedometer/odometer.

The difference in the speed before the calibration was bout 5~6 mph at 65 mph, so it was enough to get me a ticket if I was not careful.  As for the mpg, it improved, but only by about 0.05~0.1 mpg (that's more than the margin of error I figure I have, so I dont consider it).

I figure once I get around to it and take my engine apart and clean everything up nice it will improve significantly...  But that may be some years away, as this is still my daily driver, and if I take it apart, I dont have a mode of transportation!

Felipe

[jeepheap]

ok ay finally got around to doing the math one this one....
90 yj 2.5, ax5 (with no fifth gear) ,stock diffs (4.10) stock intake, cherry bomb muffler but other wise stock exhast, 4" lift 33" tires.... and mind you this is while i was towing my time out camper, about 350lbs fully loaded....
i was getting 19.5 mpg!!! i am so happy. got figure it out with my next check (to be able to get a full tank) and my gps with out the trailer.

[chardrc]

are you kidding me i couldn't get that rolling downhill with my 2 inch lift an 31's.