help - poor gas mileage is killing me

tjkj2002 · **Posted:** Tue Feb 06, 2007 6:54 pm

Heck mine only gets 12-14mpg and I think that's awsome!!!!Then again I was used to a '84 F-150 that only got 3mpg.The best I ever saw was 23mpg when my KJ was all stock.

sleeve84028 · **Posted:** Tue Feb 06, 2007 7:01 pm

I'm not complaining about my mileage... But there are things that can be done to increase the effeciency of the vehicle, to a point... That is where the "Drive slower" comment comes into play. :lol:

tommudd · **Posted:** Tue Feb 06, 2007 8:41 pm

Yes there are several things you can do but it really gets to me when some one buys a 4wd vehicle and then complains about the mileage. I am like tjkj2002, one of mine was a 79 F150 with 40s on it and I never got over 8-10 mpg and I took it to Fla. Texas and all over, drove it like I stole it! Had all kinds of fun!
One of the main things that I read is some one had some kind of little Japanese vehicle car, then jumps into a Jeep and still wants 30 MPG, as my Grandfather would always say "It aint going to happen!"

LiLredLibby · **Posted:** Tue Feb 06, 2007 8:45 pm

Tokyojoe wrote:

1. New plugs
2. OEM Air intake and filter
3. Standard size tires and wheels (235/70/16)
4. Remove armor (skids) and rock rails
5. Remove any lights on roof
6. remove roof basket
7. Change oil
8. check for proper tire PSI
9. Check alignment
10. injectors need cleaning?
11. remove lead from foot

:lol:

I'd have to agree with this list. Stock,there not too bad,but ever since my 265/75,I'm with kolsey,12 to 14 in town, and 16 at best ,on highway.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

LiLredLibby wrote:

Tokyojoe wrote:

1. New plugs
2. OEM Air intake and filter
3. Standard size tires and wheels (235/70/16)
4. Remove armor (skids) and rock rails
5. Remove any lights on roof
6. remove roof basket
7. Change oil
8. check for proper tire PSI
9. Check alignment
10. injectors need cleaning?
11. remove lead from foot

:lol:

I'd have to agree with this list. Stock,there not too bad,but ever since my 265/75,I'm with kolsey,12 to 14 in town, and 16 at best ,on highway.

I have to agree with this list. Stock, the fuel economy is about is good as you're going to get. Allowing more air into the intake causes the computer to add more fuel. You get more power, but less economy. How you drive makes a huge difference too. I can get 20 mpg on the interstate even with the 4.10 gears and without removing any weight. Got 24 mpg with the 3.73 gears. Of course, I get less than 1 mpg at the track.

edit:
Remove that throttle body spacer too.

snowsport · **Joined:** Tue Oct 18, 2005 11:52 pm **Posts:** 1211

I tried to figure out my gas mileage once but got confused and gave it up. We have liters and kilometers and I don't know what that means when I figure it out anyway. All I know is, the Jeep sucks gas like an old rummy and I'm buying the drinks. Oh, well, it is fun getting around in it!

brogrimm · **Posted:** Tue Feb 06, 2007 9:45 pm

The previous owner (my brother and his wife) did some nice mods to the Libby. They set it up for offroading without going overboard. (Okay, so overboard is nice too!) I have boulderbars, three skids plus gas tank skid, roof rack with two lights, bull bar w/brush guard & two lights, 31" MTRs on 15" wheels, and a full spare (relocated now to the rear door mount).

I have a 73 Chevy 4x4 pickup that gets about 7mpg at best so I know not to expect good mileage. I just wanted to get an idea if 12-13mpg with the extras is "normal" or overly poor. It sounds like I'm not far off the mark of what most of you are seeing.

I was going to reset the computer as I know that is good to do periodically even without mods. I did that on my 4wd Civic wagon (yes, they did make those) and it helped each time.

What plugs (make & part#) do you recommend? I've always used NGKs in my Hondas, but I'm new to the Jeep way of life.

Thanks ya'll!

Erick

2002 Liberty Sport
15X8 Black Craiger Steel Rims
31" MTR's
2.5" Rustys Suspension lift
Modified front bumper
Roof Rack with Hella 500 Lights
Rustys Transfer case skid
Kilby Gas Tank Skid
Custom air intake system with K&N cone filter
Rear shock mount relocated and Doestech shocks
All J Boulder Bars
Hidden Hitch receiver
Rocky Road Outfitters Rear Diff Guard
Cobra 75 WX ST CB with Firestick Antenna
Husky Floor Liners
Tal & Hadas Brush & Grill Guards

sleeve84028 · **Posted:** Tue Feb 06, 2007 10:17 pm

Well that explains it...

Reduced Aerodynamics - not helping
Extra Weight - not helping
Larger Tires - not helping

You're probably getting the best gas mileage possible if that picture is your Liberty

RFCRD · **Posted:** Tue Feb 06, 2007 10:18 pm

tommudd wrote:

Thats Right BVCRD, better mileage and should last longer. I should have since my wife likes the smell of Diesel, strange woman, never met a woman who liked the smell of diesel in the morning :lol:

psssst....let you in on a secret. CRD's don't smell like a diesel. They have a funky sweet smelling exhaust. :wink:

Skipperb · **Posted:** Wed Feb 07, 2007 9:12 am

Checking the milage going from Atlanta to Knoxville did it two times with the rack and three without and found that My foof rack DID NOT make any diffrence,that why I ask ( how much do you think my rack made with mpg).I don't put the spare tire on it.When I had it on it was empty.
When we went to the FL Keys it had 2 coolers and it did make a big difference.The coolers sat up about a foot over the rack. I changed to clear lexan( 1/4 ) and added the lights. Pulling the boat (22"cc 3800 )it gets 11mpg and my old bronco (98 350 4x4 ) gets 10mpg with the boat or without go figure. ckick on pix

McMoney · **Posted:** Wed Feb 07, 2007 3:56 pm

snowsport wrote:

I tried to figure out my gas mileage once but got confused and gave it up. We have liters and kilometers and I don't know what that means when I figure it out anyway. All I know is, the Jeep sucks gas like an old rummy and I'm buying the drinks. Oh, well, it is fun getting around in it!

All i know is that 25 mpg is about 10 L/100km. My CRD gets this mileage, aint too bad

wendell · **Posted:** Wed Feb 07, 2007 4:17 pm

I don't know if it will help on the kj, cause all I've done is put mobil 1 in at the first oil change. But on the ranger I put all synthetic fluids from the motor to the rear diff. I went from 18/21 to 22/24. I will be doing the rest of the kj's fluids this summer. Also the ranger got an intake, cat back, headers, udp, e-fan and programer as well, so it might not all be the synthetics, but they sure didn't hurt.

Northbee · **Posted:** Mon Feb 12, 2007 10:34 am

McMoney wrote:

snowsport wrote:

I tried to figure out my gas mileage once but got confused and gave it up. We have liters and kilometers and I don't know what that means when I figure it out anyway. All I know is, the Jeep sucks gas like an old rummy and I'm buying the drinks. Oh, well, it is fun getting around in it!

All i know is that 25 mpg is about 10 L/100km. My CRD gets this mileage, aint too bad

It's easier than it looks -

a) To convert mpg to L/100km

1) multiply your mpg by 1.609 to get km per gallon (25*1.609=40.225 km per gallon in our 25mpg example)
2) divide your km per gallon by 3.7854 to get km per liter (40.225/3.7854=10.63 km per liter)
3) divide 100 by your km per liter to get L/100km (100/10.63= 9.407 L/100km which is even better than 10L/100km)

b) To convert L/100km to mpg (let's use the 10L/100km as example)

1) divide L/100km by 3.7854 to get gallons per 100km (10/3.7854=2.6417 gallons per 100km)
2) divide the 100km by 1.609 to get miles -> 62.15 miles (so we have 2.6417 gal per 62.15 miles)
3) divide 62.15 by your gallons per 100km value to get mpg (62.15/2.6417=23.5265 mpg)

BVCRD · **Posted:** Mon Feb 12, 2007 10:48 am

wendell wrote:

I don't know if it will help on the kj, cause all I've done is put mobil 1 in at the first oil change. But on the ranger I put all synthetic fluids from the motor to the rear diff. I went from 18/21 to 22/24. I will be doing the rest of the kj's fluids this summer. Also the ranger got an intake, cat back, headers, udp, e-fan and programer as well, so it might not all be the synthetics, but they sure didn't hurt.

No worries. You are already full synthetic.

LostRenegade · **Posted:** Mon Feb 12, 2007 9:03 pm

Video Guy wrote:

Does this 12mpg Liberty have oversized tires on it? (Most of us here have upgraded to larger tires.) A tire bigger than original equipment will cause you to log false mileage on your odometer, because it requires fewer rotations per mile. So you might be driving more miles per tank than what your KJ is telling you. That would affect your mpg calculations.

Yes, but I have had the wheel RPM reflashed on the BCM to accomidate for the larger tires. I only get 12 in the city. I get about 15 -16 on highway and expressways, but only as long as I keep it under 70.

LiLredLibby · **Posted:** Mon Feb 12, 2007 9:29 pm

LostRenegade wrote:

Video Guy wrote:

Does this 12mpg Liberty have oversized tires on it? (Most of us here have upgraded to larger tires.) A tire bigger than original equipment will cause you to log false mileage on your odometer, because it requires fewer rotations per mile. So you might be driving more miles per tank than what your KJ is telling you. That would affect your mpg calculations.

Yes, but I have had the wheel RPM reflashed on the BCM to accomidate for the larger tires. I only get 12 in the city. I get about 15 -16 on highway and expressways, but only as long as I keep it under 70.

When I went to 265/75/16s I did'nt need to calculate my mileage loss,it was obvious that I was going to the station more often.My driving schedule is basicly always the same,but my fueling schedule did change and I really did'nt expect anything less. :wink:

wendell · **Posted:** Tue Feb 13, 2007 8:45 am

Which fluids in our drivetrain are synthetic? I just put mobil 1 in the motor. So let me get this straight, the tranny, t-case and rear diff allready have synthetic fluids, or no?

sleeve84028 · **Posted:** Tue Feb 13, 2007 9:45 am

ATF is synthetic

The diff oil could be dino based or synthetic from the factory, I'm not sure.. my guess would be the basic stuff

The engine oil is dino based from the factory

BVCRD · **Posted:** Tue Feb 13, 2007 9:49 am

ALL fluids in mine are synthetic from the factory.

2006 KJ · **Posted:** Wed Feb 14, 2007 7:50 pm

my liberty has the K&N air intake (full kit).. and a magnaflow muffler and that boosted it to about 21 mpg from 16ish. it's also a 6 speed so it depends how hard i drive it. I put mopar roof lights on it and now getting about 1 mpg less than i was. Winter is also taking it's hit. Idleing to warm up.. and running in 4wd most the time has dropped it to about 15mpg. not all that horrible!

help - poor gas mileage is killing me

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