I checked this week-averaging about 17mpg combined on a '98 Sahara with 5 speed and entirely stock height tires/gearing/suspension. Most of the driving is in town with some highway, probably a 75/25 split, respectively.
What gas mileage are you guys getting?
- Thread starter DropTopDon
- Start date
OP
I had a 19 gallon tank factory but previous owner must have swapped it to 14 for some reason. I am just curious how many miles other TJ owners can expect in a tank.
LONGJP2
TJ Expert
It's not rocket science.
If you calculate your mileage by dividing known miles by the gallons that you put back in to fill up, and you know your tank size (not guess), then you can calculate the range (miles per tank) for your vehicle. Knowing someone else's guess does nothing for you.
If you calculate your mileage by dividing known miles by the gallons that you put back in to fill up, and you know your tank size (not guess), then you can calculate the range (miles per tank) for your vehicle. Knowing someone else's guess does nothing for you.
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LONGJP2
TJ Expert
Jamison C said:
All TJs came with 19 gallon tanks, but 4cyl models had a modification in the fill tube to only accept 15 gallons. This is easily reversed by cutting back said tube. I assume this had to do with shaving weight after filling up.
Why do you think it's a 14 gallon tank? Have you run it dry, and filled it up. Don't assume it's empty just because the gauge says so.
And again, everyone's miles per tank will be different, so it's irrelevant.
OP
Again, was not writing this thread with the intent of calculating my own gas mileage. I am already aware of my mileage in my TJ. My reason for posting this thread was simply because I was curious what other TJ owner's were expecting out of their jeeps. Everyone's will relatively be different or else what would be the point in me asking. Also yes I have ran my TJ bone dry out of gas before and it filled up no more than 14 gallons.
I usually go about 280 miles between fill up, and the fill up is around 16 gallons, give or take.
Winks42
TJ Enthusiast
OP
I have a 6 cylinder but my jeep only holds 13-14 gallons max when it is completely empty. I always thought the previous owner before me had swapped out the fuel tank but i see no reason he would do that. Do you think it is possible my 6 cylinder somehow has this modification in the fill tube?
The PO could have damaged the original tank on a trail and just replaced it with a 4 cyl one. I didn't read the "how to" on the hose thing, but it looks pretty easy. You might be able to unscrew the hose and just check the length.
OP
That is possible but I don’t think he wheeled it much because it was bonestock when I purchased it from him. Not sure though, thank you and I’ll definitely research that.
When I first did my engine swap with 33in mud tires and 3.07s and worn suspension I was get 26 mpg. With poorly worn mud tires and rack I was getting low 20s mpg. Dropped down to original sized tires (and mass) with the rack and average 24 mpg regularly for the average tank. Low 20s still with city driving.
Hopefully finishing up my regear 3.73 and suspension/steering and going to 33" mud tires (which I'm going to have to replace the fronts from how badly cupped I let them get), I figure I can get 24 mpg highway. I plan to run something around a 30" all terrain during the summer when we're going to the lake and towing stuff like our fishing kayaks, I expect to get probably 26 mpg again on highway. Probably around 20mpg when towing with those tires and gears.
I was getting around 11 mpg with mud tires and the 4.0 and 3.07s. Oh I'm running the AX-15 and haven't changed.
I do think TJs are capable of 30ish mpg, but you're gonna need to really look at what's mounted to the Jeep, your tires, your gearing and your right foot etc. Also you probably have to delete all emissions equipment. Cummins claims they were getting low 30s with their prototypes and I've had a VERY similar setup, but I wasn't able to adjust my tune like they could. I do plan on a mild tune, just to slightly adjust the drivability. Apparently Cummins was very close to releasing a 180 hp/360 ft lb tune. Cummins techs suggested a few tweaks would have 10% better MPG. That's not my goal though. I just wanted a slight bump in range and I want the new engine to be as reliable as possible, hopefully similar reliability to the 4.0 I pulled out.
Personally once you're in the 20s MPG, it just seems like you don't have to plan so tightly around gas stations when driving.
Hopefully finishing up my regear 3.73 and suspension/steering and going to 33" mud tires (which I'm going to have to replace the fronts from how badly cupped I let them get), I figure I can get 24 mpg highway. I plan to run something around a 30" all terrain during the summer when we're going to the lake and towing stuff like our fishing kayaks, I expect to get probably 26 mpg again on highway. Probably around 20mpg when towing with those tires and gears.
I was getting around 11 mpg with mud tires and the 4.0 and 3.07s. Oh I'm running the AX-15 and haven't changed.
I do think TJs are capable of 30ish mpg, but you're gonna need to really look at what's mounted to the Jeep, your tires, your gearing and your right foot etc. Also you probably have to delete all emissions equipment. Cummins claims they were getting low 30s with their prototypes and I've had a VERY similar setup, but I wasn't able to adjust my tune like they could. I do plan on a mild tune, just to slightly adjust the drivability. Apparently Cummins was very close to releasing a 180 hp/360 ft lb tune. Cummins techs suggested a few tweaks would have 10% better MPG. That's not my goal though. I just wanted a slight bump in range and I want the new engine to be as reliable as possible, hopefully similar reliability to the 4.0 I pulled out.
Personally once you're in the 20s MPG, it just seems like you don't have to plan so tightly around gas stations when driving.
Mazepam
TJ Enthusiast
I have 31's and im assuming a 19 gallon take as that's what i use to calculate this, 6 speed manual. I'm getting around 11-13 miles per gallon, but I'm assuming that my speedometer is off by around 10% because of the larger tires.
In a month or so ill install a 3.5 inch lift and put 33's on it, ill report back then to what im averaging.
In a month or so ill install a 3.5 inch lift and put 33's on it, ill report back then to what im averaging.
let see there's 2 pints in a quart, 4 quarts in a gallon......how many gallons in a watt
IT'S NOT THE MPG IN A WRANGLER, IT'S SMILES PER GALLON ! i get about 50
Stock 4-litre, 5-speed 3550, 31" tires on a 2000 mile trip from TX to MA averaged 18 MPG with cruise set at 70MPH.
After going through 9 tanks of gas I'm confident of having 4 gallons in the tank when the low-fuel light comes on.
Speedometer was within 1-2 MPH of GPS and OBD II readings.
Right now I'm in the process of changing all fluids and filters, (and maybe cats, recurring P0432!! Yes I used NTK)
After going through 9 tanks of gas I'm confident of having 4 gallons in the tank when the low-fuel light comes on.
Speedometer was within 1-2 MPH of GPS and OBD II readings.
Right now I'm in the process of changing all fluids and filters, (and maybe cats
, recurring P0432!! Yes I used NTK)
Mazepam
TJ Enthusiast
Ha yeah its pretty bad! I'm new to manual transmissions though so maybe that could be a reason. I try to keep it between 2-3k at most times though.
I know my speed is off dude the tires its off by around 10% as the miles get bigger, so that would equate to around 13-16 mpg. I thought TJ's averaged about 15 mpg.
Mod is not to the fill tube but rather the vent tube. The early SE's fuel tanks had the vent extended lower into the tank which shuts the fuel nozzle off earlier. It just has to be shortened internally.
My fuel economy went up a bit after I started to change at higher revs as suggested by a few on here which sort of went against my logic but it worked!
Except 1st to 2nd which I have now started a gentle low rev change and the dreaded 6 speed 1st-2nd non mesh has gone I change 1st -2nd at speeds like I would a truck or what ever you call them in US? Actually what do you call a heavy vehicle given everyone seems to call their pickups a Truck? lol
Also my 6 speed is hardly ever in 5th or 6th, I now run it as a 4 speed unless on the highway, last straight 6 cylinder I owned had a 3 on the Tree (Column shift) Ford Falcon, I dont think TJs need all them gears!