Keith12jk

Ok so I got this Jeep and it already has a lift with tires on it. I bought a trail dash 2 tuner and assumed it has 3.73 gears as its an 2012 auto. Went to program that in with my 33" tires and the damn thing lost its mind and sent the jeep into limp mode....Looked at window sticker and it says in standard options it has a 3.21. Programmed that into the tuner and it works fine but my speedo is 4-5mph faster than it should be...Went to go look on the rear pumpkin and its been replaced with poison spyder diff covers front and rear, so no stamp......

It is my first jeep n all but I'm gonna say its a slug. Any ideas as to..

A.) Figure out what gear ratio I have?

B.) Is something wrong with my tuner?

resharp001

Assuming nobody has swapped axles, you could call the dealer with your VIN and get the build specs (edit - sorry, didn't originally see the window sticker said build was 3.21 gears). You could also put the front axle on stands and turn the front drive shaft by hand, counting the rotations it takes to rotate the tires 1 full turn. A little over 3 DS rotations would be 3.21....a little less than 4 rotations would be 3.73, and a little more than 4 rotations would be 4.10.

Once you have the gears figured out, be sure to program the ACTUAL tire height. Don't plug in 33" cuz it is almost guaranteed they are not measuring 33". Take a tape measure and a level over the top of the tire and measure the actual height.

jadmt

you never have to program in the gear ratio unless you change gears. If it is not in limp mode with where you have it now just reprogram for tire size change. If it were mine I would go from there and see what happens. If it is a procal you have just reset everything to base and start over and don't mess with the gear ratio.

Keith12jk

Took what you said into account per thats what it said in the super chips manual....still Fed.....

resharp001

Are you comparing the speedo to what the traildash displays, or what a GPS shows you're traveling at? Indeed seems like a big discrepancy outside of being way off measurement wise.

Keith12jk

SO the speedo on the Jeep and the speedo on the Traildash 2 tuner are both reading the same. However, I did grab a friend with a completely stock car and kept 100% pace with him on the roads. Im off 4-5 mph no matter what gear or rpm. Guys at Superchips just keep saying i haven't installed it right or I haven't updated it right. Which I have.... Looks like I wasted $450 and will be going to a new company.

Thanks for trying to help me btw.

resharp001

I wouldn't throw in the towel yet. Superchips is a reputable company, and although I've not used a Traildash myself, their other products I have seen/used are very good and user friendly. IDK, I wouldn't trust a comparison with the stock jeep myself. I compare to a handheld GPS myself. Even GPS on your phone would probably be a better gauge. I will say that even when measuring the exact height, sometimes have to tweak the programmer setting just a bit one way or the other still.....but that is to dial in the last 1mph or so, not 5.

I have a Bullydog myself (which I could never recommend) and have had times in the past where I thought the change was taking but it didn't. After many troubleshooting efforts over months, realized it was user error....LOL. When you go back to that setting, does it still reflect the measurement you put in last time? I'm sure you'd realize if the setting was sticking or not....but just trying to rule out any issue.

jadmt

an easy way to see if the tire size is being programmed is to input way over size and see what happens if nothing changes then it is not programming. I would reset everything to base and go from there if it were me.

ronjenx

The computer that is telling your speedometer what to display is also telling your Traildash what to display.