FLKEYSJK
Member
Haha it's ok just making sure because I want to check my axle ratio.
MPG Issue/question?
- Thread starter JKHunter817
- Start date
Haha it's ok just making sure because I want to check my axle ratio.
cozdude
Guy with a Red 2-Door
Yes you are right. If you have 4.10 gears than the driveshaft will rotate slightly more that 4 times for every one tire rotation. If you have 3.73 than the DS will rotate slightly less than 4 turns for the one tire rotation
JKHunter817
New member
Yeah I have the 4.10 gears as well
JKHunter817
New member
I just did this and got rid of the blinking sway bar light, also the check engine for the Evap, I went in and cleaned out the lines and connectors by the battery and had a worn spot on one, did the electrical tape wrap to see if it fixes the small leak. Hope it's not just temporary and actual fixes the problem haha
Mike_JK_Houston_711
New member
Glad to hear this worked. Yea, report back if you're still having issues with anything. You can also run your own DTC real quick by holding your key in the ignition and turning it ON and OFF three times quickly, ending with ON. Don't turn the engine over during any of those cycles. Your dash will report codes back to you if there's anything else out of whack.
teamahh
New member
+1 on the procal. I have 35's and a 3.75 lift. Had similar issues of pretty low MPG reading and obviously my speedo was off by a few mph. After updating the comp with the procal, my mpg reading was on avg 2-3mpg better. I drive 50% city and 50% hwy as my DD. It used to show no more than 13mpg, now I avg 16-17 on a good day, never below 14 unless Im wheeling.
SoCalDozer
New member
I do not fully trust the computer to give you a 100% accurate reading. After you get a procal measure your tires just like this thread does http://wayalife.com/showthread.php?35075-The-Ultimate-TRUE-TIRE-SIZE-Database.
If you do this it will ensure your speedo is correctly adjusted and your mileage will be correct. Most of the time people do not set the procal correctly and just throw in whatever they think they have for tire size.
Then I would check it yourself between fill up's with a calculator to see what you are averaging.
If you do this it will ensure your speedo is correctly adjusted and your mileage will be correct. Most of the time people do not set the procal correctly and just throw in whatever they think they have for tire size.
Then I would check it yourself between fill up's with a calculator to see what you are averaging.
Hammmerhead
Member
Do you have to lock the rear diff to do this on a Rubi? I really don't want to pull the cover and count ring teeth to see what I actually have in there as my rpms don't match up with my tires on the 3.6 Auto gear chart
cozdude
Guy with a Red 2-Door
No. Just jack it up from the diff and spin.
jeeeep
Hooked
if you disconnected the battery, that would reset the lights but may not have solved the issue - you may get the lights back on after a few key cycles.
blinking sway bar light, on the Rubicon that usually means the sway bar is not released or not properly engaged to it's lock position.
Is one of the sway bar links higher than the other? maybe bent? put it in 4HI and activate to release the sway bar. once the sway bar is released let it idle then undo the links at the axle and make sure the sway bar moves freely.
Check that the links are the same length or bent. connect the links back to the axle and then you can turn off the sway bar and put it in 2WD - the light should go off.
if it still blinks and will not engage, you may have water/rust issues in the sway bar motor. there's a post on the site where a member took his apart cleaned it up and got it working again.
evap or gas cap light?
Last edited:
teamahh
New member
True, calculating it yourself would be a better way to see how far off the computer is reading compared to what your calculations show. Maybe something I will be trying here soon. :thumb:
JKHunter817
New member
Well that I may fixed this problem or not I won't know until who knows when some sorry bastard just re ended the jeep!
JKHunter817
New member
Pissed right about now...
Zstairlessone
New member
That sucks!
Also, your speedo might be as much as 10% low (same with MPG) with 35s and not recalibrating the speedo.
Also, your speedo might be as much as 10% low (same with MPG) with 35s and not recalibrating the speedo.
Jegar
New member
Mine is a 2015 Jk 2Dr Willy Wheeler, so stock was 3.73 gears and the rubi BFG KO's (that I believe equate to around 31 to 31-1/2"). I tended to get around 13.8 to 14.5. But I also tended to accelerate hard and I typically was going 70-85 on the highway and 40-60 on the street. Flat terrain with breezes generally 12-19mph.
After my 3.5" lift and 35's, and similar driving pattern, but with some downgrade on the top speeds, my uncalibrated mileage drop to the 11's and 12's, and then gradually increased to 12's and 13's, and some 14's. Some of the later improvement was some ease on my driving style, but it seemed that the computer gradually adjusted and the overall mpg improved regardless. However, the shift points were definitely off, and the rpm's seemed all over the place.
After seeing mention in multiple posts and from multiple sources about possible engine damage due to the inaccurate shift points, I got the ProCal. The calibration was crazy simple (I was so mad at myself, because I let it sit in a drawer for about 6 weeks, because I thought it was going to be a PITA). Immediately, I could feel an improvement in the ride and shift points. Likewise, my mpg improved significantly, and has continued to improve. Again, while some of the improvement is a more relaxed, steady driving style than previously, I still haven't slowed on the highway, and my rpm's stay in the high 2000's and low-to-mid 3000's. 15.3 to 15.8 is where I stay much of the time now.
Sorry! That really, really sucks!!!
JKHunter817
New member
Yeah sucks ass but I'll be looking to get a Procal as soon as I take care of this BS! Thanks guys
SoCalDozer
New member
When I had my 2 door in San Diego I was getting 18-19 mpg wit 33x12.5's and 3.21.
I'm averaging 19.5 right now stock with 3.21's on my 4 door.
I'm averaging 19.5 right now stock with 3.21's on my 4 door.