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Topic Review (Newest First)
05-12-2012 05:05 PM
bschimmel
Mileage

If your running 32" Tires with 3.07 Gears, thats why your mileage is bad. The 4.11 will help
05-12-2012 04:03 PM
KebHund
Mileage of TJ 4.0

Guys, is there any average mileage to recognize what is ok and what not? I am getting less than 10 MPG when combining town and trail. 32", 4" lift, 3,07 gears (to be changed to 4.11 next week:-), soft on pedal...
Listening you complaining about your 13 - 16 MGP I wish I had it!
12-31-2011 04:13 PM
Jerry Bransford
Quote:
Originally Posted by Rubicondon53 View Post
my Rubi " averages " 15 mpg, with medium grade gas. .
Your Rubicon would get the same mpg whether you run 87, 89, 91, or 93 octane. Octane has ZERO to do with your mpg. In fact, running a higher octane than the engine was designed to run can actually cause deposits to be left behind and the engine not perform as well and conceivably not even get as good of mpg as it could with the lower octane fuel.

How can that be? Octane's sole purpose is to make the gasoline harder to ignite and slower to burn. Octane is only added to gasoline to help keep it from igniting prematurely in high compression engines, which is why high performance (aka high compression) engines require higher octane levels.

Octane does not add power and it certainly has no ability to improve mpg. Higher octane fuesl can actually conceivably cause both to be worsened if the octane amount is higher than the engine was designed for.

Run 87 octane, your wallet and your engine will thank you... and your mpg will not decrease. Not to mention a gallon of high octane gasoline contain no additional energy content or cleaning additives than a gallon of regular grade gasoline does.

Quote:
Originally Posted by JAYH.TJ View Post
my actual milage was 200 miles until the reserve light came on then i filled it up and got 60 liters in the tank and it was brimmed and now ive done 110 miles and its nearly on the half . so i guess when it was empty it must of had about 4-5 gallons left in the tank.
In summary, pay NO attention to when your low-fue; light comes on and don't even think about using it as any part of figuring out your MPG. The low fuel light is notoriously inaccurate and when it comes on will even change as the the fuel gauge sender ages.

The ONLY way to accurately/correctly determine your true mpg is to 1) Note the exact mileage when you fill up. 2) When you next fill up, divide the exact number of miles driven since you last filled up by the exact number of gallons it took to to refill the tank back to full. That is the only accurate way of determining your mpg.

Neither the inaccurate fuel gauge position nor the inaccurate low fuel light are ever a part of the mpg calculation.
12-31-2011 03:50 PM
JAYH.TJ no thanks for the answers i appreciate it alot

my actual milage was 200 miles until the reserve light came on then i filled it up and got 60 liters in the tank and it was brimmed and now ive done 110 miles and its nearly on the half . so i guess when it was empty it must of had about 4-5 gallons left in the tank.
12-28-2011 09:55 AM
Atthehop
Quote:
Originally Posted by Remus_Redbone View Post
Figure you actual mileage. If the float / sensor it out of whack and the low fuel light is coming on when you have 4 or 5 gallons left in the tank as mentioned by a couple replies, you are getting 13 to 14 mpg and sadly that's not all that far off for 4.0L Jeep.
It looks like he has not figured his actual mileage for us to review. I guess he does not like any of our answers.
12-28-2011 09:47 AM
thetoadLJ fwiw im running 32s on 3.73s and get about 200 avg per tank depending on city/highway driving and my light comes on i have about 3 gallons left im guessing. i always fill about 16 gallons into my jeep when i hit the pump.
12-28-2011 09:23 AM
WaterDR You have to just ask around. If you stop at a marina you will find someone that knows likely. People with 2 stroke boat motors can't use it. While around here I would say that 90 percent has ethanol in it, many stations have pumps that are marked no ethanol near where people boat.
12-28-2011 07:17 AM
JeepWrangler4x4 we have a couple gas stations that offer no ethanol around here, one of them is a R-store and they just started it a few months ago and the other is fleet farm which is a all purpose store with a gas station but not sure if they still do haven't got gas from there in a while since its a 25 min drive. But my last MPG was 15.169mpg with about 75% highway driving on that tank from the holidays.
12-27-2011 09:39 AM
00tj2 Where do you get gas without ethanol???i wish I could get some of the "old gas" here in lower ny. I lost about 5 mpg average ( went from 18c-24h to around 17mpg everywhere) when they changed the fuel.
12-27-2011 12:07 AM
JeepWrangler4x4 sounds about right too, all depends on how you drive basicly.. but i average about 200 with 19 gal tank before the light comes and then i run it 2 more days and only end up putting in like 16.5 gallons, but i got a program on my phone called aCar and it does all my MPG for me, most ive ever gotten out of a tank was 17 something during the summer, and when my thermostat was stuck open it dropped it to 12.5 to 13mph, with it being winter and such it get about 14-14.5mpg all depends on if im doing city or highway driving and if im doing 60-65 on the hwy or 75-80 on highway

I also run 87 rating with no ethanol, i also run lucas fuel injector cleaner and such if i have some in my jeep at the time
12-26-2011 11:43 PM
navyspence92 It's a jeep. If you're worried about gas mileage you've got the wrong vehicle lol
12-26-2011 09:10 AM
Shelby427 And don't forget the one thing you can control, your right foot.

How you drive will greatly affect your mileage.
When my wife drives she's lucky to get 200 miles on a tank. Me? I've gotten over 300.
12-26-2011 09:08 AM
Rubicondon53
Quote:
Originally Posted by Black98
Gotta calculate MPG using the good old trip/amount required to refill back to full. Using the fuel guage in anyway on these Tjs will mislead and worry you. I always calculate MPG on every tank because dips in MPG often can help show a problem before any idiot code ever appears.
Agreed 100%. My kids think I'm anal about MPGs, my Rubi " averages " 15 mpg, with medium grade gas. If it dips, I know something needs fixing, way before idiot lights will warn me, and way before it just quits running.. I learned to clean the throttle body, the idle control, and all the sensors because of dips in MPGs.
12-26-2011 03:48 AM
WaterDR Not unless there is ethanol in it. And if there is, it will still be mostly gasoline.
12-26-2011 12:16 AM
XJ Knight Is it winter in England? Winter grade gas perhaps could be a contributing factor if they use that in england. It will hurt your mpg a bit.
12-25-2011 10:11 PM
Black98 Gotta calculate MPG using the good old trip/amount required to refill back to full. Using the fuel guage in anyway on these Tjs will mislead and worry you. I always calculate MPG on every tank because dips in MPG often can help show a problem before any idiot code ever appears.
12-25-2011 10:07 PM
Remus_Redbone Figure you actual mileage. If the float / sensor it out of whack and the low fuel light is coming on when you have 4 or 5 gallons left in the tank as mentioned by a couple replies, you are getting 13 to 14 mpg and sadly that's not all that far off for 4.0L Jeep.
12-25-2011 10:03 PM
Rubicondon53 200 miles is about right,,, that's what mine does with 4:11s and 33s. It seems early, but it's happening around 1/4 tank, as I usually put 14 or 15 gallons in at that point..
12-25-2011 09:35 PM
sevenservices ^yeah. Also make sure you don't have a low tire somewhere... causes a lot of extra drag. Same w/brakes if they are dragging in the back or something.
12-25-2011 09:30 PM
zdragon
Quote:
Originally Posted by AntiTrust View Post
16.5 for my JK

that's above average gas mileage for a Jeep.
12-25-2011 08:35 PM
AntiTrust 16.5 for my JK
12-25-2011 07:21 PM
1jeeplvr I think you should figure what your actually getting for fuel mileage.My XJ only gets 15-16 mpg.
12-25-2011 07:15 PM
ejxjohnson
Quote:
Originally Posted by Mr_RPM View Post
when you fill back up does it take close to 19 gallons?

my light sometimes turns on at 200 miles but I usually still have 4-5 gallons left. the fuel gauge lies and says its empty waaaay before it is.
what he said! when my light comes on i usally ave around 200 and i drive around for another day or so and get gas and most of the time im only putting 16 or 17 gallons in for a full tank.
12-25-2011 07:04 PM
Mr_RPM when you fill back up does it take close to 19 gallons?

my light sometimes turns on at 200 miles but I usually still have 4-5 gallons left. the fuel gauge lies and says its empty waaaay before it is.
12-25-2011 07:03 PM
sknybkr44 I get about the same with mine
12-25-2011 07:00 PM
rrich Check for an exhaust leak ahead of the O2 sensor.
The exhaust pulses, pressure to vacuum. A leak lets Oxygen get to the O2 sensor, causing it to run rich.

Dribble a little oil down the throttle body to make it smoke a little, stuff a rag in the tailpipe to pressurize the exhaust, then go underneath with a strong light to see where smoke's coming out.
12-25-2011 06:45 PM
Joshpeb2
Quote:
Originally Posted by JDsDream View Post
Welcome to the Forum

There are several factors that can effect mileage including the octane rating or the ethynol content of the fuel itself. I have an 06, 4.0 I6 and 200 to 230 is about all that I get out of mine.
Mine is an 05 but, thats about all I get outta mine too. If I push for 235 I'd be walking. Mine could use some new plugs though.
12-25-2011 05:45 PM
AntiTrust almost smell the exh and make sure its not running rich, IE no high fuel smell
12-25-2011 05:36 PM
JDsDream Welcome to the Forum

There are several factors that can effect mileage including the octane rating or the ethynol content of the fuel itself. I have an 06, 4.0 I6 and 200 to 230 is about all that I get out of mine.
12-25-2011 05:21 PM
JAYH.TJ I think the injectors are ok because the jeep runs great lots of power and there is no faults codes or no rough running,
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