Whats your MPG

[WaXJ_Skier]

Thermostat maybe? If the computer isn't detecting it getting up to temp it will run rich.

 

[crazymoose1990]

I put a 190 in it when I bought it? What temp should it run at? 180 normally right?
When we where on the Christmas tree run it was running at 200 most of the day. Thats reminds me weren't you coming down for that run, or did you and I am slipping.

 

[WaXJ_Skier]

I put a 190 in it when I bought it? What temp should it run at? 180 normally right?
When we where on the Christmas tree run it was running at 200 most of the day. Thats reminds me weren't you coming down for that run, or did you and I am slipping.

195 is a stock but the gauge sensor and the computer sensor are at opposite ends of the block so I would guess the computer sensor would read cooler as it sits in the thermostat housing.

 

[dellstopjeep]

4.0 ax-15, 35's and 4.56's with hubs I pulled 17 to 18 highway and 15 around town. I dont care about weight.

The 98 with 4.0, aw4, 35's and 4.56s gets 15 highway tops.

The 5 speed helps out a ton

 

[cody4359]

when i first got the mj (4.0, 4.10 and 33) i got 17 mpg going down to vancouver. after a banks torque tube, catback, throttle body spacer ive been around 15 mpg going back and forth to seattle. 7.5 mpg for the last 68 mi snow trip

 

[dfarmxj]

Just over 16 mpg. 4.0,auto, 3.55's,31"x10.5"s. I suspect it may be a little better, because I haven't corrected my speedo yet. I drive 2 lane back roads mostly and use cruise control a lot. I noticed about a 3mpg improvement just from using cc most of the time.

 

[moneypit_k5]

I must be in mine way to much, I wished I got over 15. I do have my suspitions that I am running rich, my exhaust pipe is as black as coal. Its fuel injected but something sure seems wrong if Im getting 10 MPG and you guys are getting 15 and 20 MPG

i was in the single digits until i replaced my old tired injectores with some new bosch 4 hole units.

now im getting 15mpg flat out with a 5200lb jeep and mega wind drag.

 

[XJ_ranger]

My polaris 600 gets about 7 mpg in deep powder. :thumbup:

 

[moneypit_k5]

stupid double post.

 

[RumbleGoat]

On 235/75R15's, AX-15, and 3.07's I get 18+ in town and 23-24 on the highway. .

I was right there with the same set-up. In the neighborhood of 18 Hiway and 15 combined with 31s now. Interested to see what happens after the regear. Based on how the engine feels, I think it will be happier with a few more Rs on the freeway.

 

[WheelinJR]

I put a 190 in it when I bought it? What temp should it run at? 180 normally right?
When we where on the Christmas tree run it was running at 200 most of the day. Thats reminds me weren't you coming down for that run, or did you and I am slipping.

195* is the OE thermostat temp, but operating temp is 210.

 

[dick.breakey]

195* is the OE thermostat temp, but operating temp is 210.

i havent hit 210 since ive owned the jeep. i barely hit 170 if im lucky

 

[dellstopjeep]

You need to buy or borrow a infarered thermometer and get some real time engine temps. Checking the radiator, thermostat housing, and side of block in comparison to your engine temp on the gauge.

 

[WheelinJR]

i havent hit 210 since ive owned the jeep. i barely hit 170 if im lucky

Then something isn't right. At first guess I would say you need a new thermostat (stuck wide open)

At that temp its very likely that your ECU isn't seeing the Jeep up to temp. Not sure if the HO ECU's keep timing pulled and fuel rich until its up to temp, but if it is, you're likely losing power and efficiency because of it.

 

[crazymoose1990]

If your Jeep is actually running that cold, your oil is going to look like sludge.

 

[dick.breakey]

Well we'll see when I change the oil next time. I actually meant to get an infrared thermometer the other day but forgot. We'll see what it says when I do. And considering I was getting 20+ mpg before the bigger tires I doubt it's having too much affect on efficiency.

 

[hards91xj]

My mpg`s
Motorhome 5.7-6.5.....o2 Ranger 16.5-19.0....90 Toyota pickup 16.5-18.5....2011 GMC terrain 22.5-33....Oh yea the 91 XJ -11-16..with the 98 engine and regear 4:56 and 32.11 tires