My brother is getting pathetic gas mileage in our YJ with a fresh new 258 and a webber carb. We rebuilt the rig after a fire. We have never owned a 258 before or a carb motor for that matter.

It is only getting about 10 MPG.

The rig has the TORQF. 999 3 spd auto and it runs at nearly 3500 rpms at hwy speed.

Is this the way that all YJ wranglers are with the 258?? How many miles per gallon do you guys get in those CJ's with 258?

We titled the rig as a 1978 CJ7 so all the Emissions Crap has been eliminated except for vacume advance on the dist and manifold vac for the brake booster and the 4wd.

I think that the rig is running a little rich but I dont know how to adjust the carb at high rpms to get better gas mileage.

WHAT CAN WE DO TO THIS THING TO GET THE MILEGE UP A LITTLE BIT SHORT OF REPLACING THE BBL WITH A FUEL INJECTION KIT OR A MPI CONVERSION??




ALSO I am getting oil into my antifreeze... but there is no antifreeze getting into my oil. Sounds like a highpressure oil leak to me?? What do you all think?? I have a 7/70 warranty on the engine so it is going back to the shop on Thursday Morning??


Again all help is appreciated.

Ouch!

My 304 is getting better mileage than you.

I lowered my idle speed, becuase I was burning most of the fuel stuck in traffic. It helped on mine. Also rebuilt the carb.



As for oil in the coolant, that seems like it would be as you said, high pressure leak in the block.

I was getting about 12mpg with my 258 with the Weber carb. in my "88" wrangler. I am running 32 MT's with stock gears right now. I replaced the carb. with Howell TBI and get 18 mpg. That driving 60-65 on interstate. I use it as my daily driver, 300-500 per week. I found a used Howell system and installed it. You can buy a Weber carb. manuall in some of the 4-wheel mags for about
13.00 bucks that will tell you how to adj. Hope this helps..

I would check for vacuum leaks also check if it's running lean or rich. Your trany should also have a lock up converter, is it working? As far as rpm's what gears and what size tires?
I run the 258 with the 999 with 4.88 and 35" tires and turn 31-3200 at 60 mph.

well my '94 YJ 2.5L with the auto and 4.56 gearsgets about 11 miles to the gallon. I get 3500 RPMS going 60, for some reason the torque convertor never locks up, except for once a month. So maybe this is normal.

I got 35's w/ 4.1 gears, 2400 RPMs @ 60 and get about 14 MPG. You'll find it hard to get any more mileage when you are turning those hogh RPMs @ highway speeds.

i used to get 20-22mpg on the highway in my 81 cj-7 with 2.73 gears, 31" muds, and a rebuild 258 with some kind of "RV" cam. also, i was only running around 1800 RPM at 60 mph.

matt

How are you guys having a lock-up torque converter with a non overdrive transmission? I didn't think they did that, but I'm not big on Jeep automatics. Anyway, my '95 4cyl still gets 12-14mpg at 4000 rpm @ 75 mph (SM420 4sp, 5.38's and 35's) fuel injection rules.