Cheech Posted October 19, 2009 Share Posted October 19, 2009 Well, I have been driving the MJ quite a bit more and have finally run a few tanks of fuel through it. I have been writing down the kilometers at every fill up. Filled up tonight, and as long as all my conversions are correct, I am pulling only 15mpg. Not sure what to make of this. Its an 86 2.5 TBI 4x4 , with the 3 speed auto. I am assuming the high rpms that I have to run at hurts the fuel economy a fair bit. What are others getting with this engine/trans setup? Link to comment Share on other sites More sharing options...
mnkyboy Posted October 19, 2009 Share Posted October 19, 2009 I stay around 18mpg with the TB 2.5L and AX4 running 31s with stock gears. my brother has a 95 YJ with MPFI 2.5L and AX5 and somehow gets a little worse mileage then i do. Link to comment Share on other sites More sharing options...
ratrapp Posted October 20, 2009 Share Posted October 20, 2009 my 88 4.0 with aw4 and 235s only gets 15-16 mpg.i do do most of my driving around town though.it may get alittle better on the highway.this is 165k mile tired engine with a k&n,redline in the the diffs and t-case and a high flow converter with 2 1/2 exhaust. Link to comment Share on other sites More sharing options...
Pete M Posted October 20, 2009 Share Posted October 20, 2009 what size tires? mostly city or mostly highway? how fast do you normally drive on the highway? Link to comment Share on other sites More sharing options...
WBKrazy Posted October 20, 2009 Share Posted October 20, 2009 mine is an 88 with 116k on it, 2wd with the 2.5 and an ax4 with the stock size tires - i drive it mostly highway, and it gets between 21-22 mpg.. course that was before the motor blew, now it just kinda sits awaiting resurrection Link to comment Share on other sites More sharing options...
Rockyrider367 Posted October 20, 2009 Share Posted October 20, 2009 Ive got an 86 2.5 5spd 35's with 4.56 gears and on highway I'm getting about 20mpg to 22mpg. I have no idea how Link to comment Share on other sites More sharing options...
Cheech Posted October 20, 2009 Author Share Posted October 20, 2009 what size tires? mostly city or mostly highway? how fast do you normally drive on the highway? I am running stock size tires. I do basically all highway with a little driving around the farm, but not much really. For speed I usually stick to 90 kilometers/hour. Even at that speed the engine really has to rev. The truck has about 183,000 kms on it. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 20, 2009 Share Posted October 20, 2009 This truck probably has 4:56 gears. I'm not sure if it has a lockup converter or not, but if it does and it isnt locking, maybe that could be the issue.... also put in a new O2 sensor, that will help also. And maybe convert from engine fan to electric fan, cold air tube. I would think you should get at least 20MPG. And is your speedo right? maybe thee trans has been swapped and has the wrong speedo gear in it... just some stuff to check. Good luck! Link to comment Share on other sites More sharing options...
Pete M Posted October 20, 2009 Share Posted October 20, 2009 See if either axle has the little metal tag on the diff cover. Link to comment Share on other sites More sharing options...
Cheech Posted October 21, 2009 Author Share Posted October 21, 2009 Who made the 3 speed transmission in my truck?? edit: I should say who make the 3 speed in the MJ's?? Link to comment Share on other sites More sharing options...
offroader461 Posted October 22, 2009 Share Posted October 22, 2009 i have 33's w/4.10's (4.0L 5spd) and i average 16-18Mpg. But my trip-meter/speedometer are off a bit b/c i don't have the exact speedo gear i need. Its close enough for me though..only 1 tooth difference Link to comment Share on other sites More sharing options...
Tri_X_Troll Posted October 23, 2009 Share Posted October 23, 2009 Who made the 3 speed transmission in my truck?? edit: I should say who make the 3 speed in the MJ's?? http://www.offroaders.com/tech/jeep/tra ... ry-904.htm http://www.jeepforum.com/wiki/index.php/30RH_/_32RH It's a pretty bad transmission. I've spent more money fixing the one in my first jeep than I did on all of my other mods combined. Link to comment Share on other sites More sharing options...
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