Bad Milage YJ!

[Megamole]

What kind of milage should an 89 Wrangler 6cyl, weber carb, 5spd, 3.07 gears, and 31" a/t tires get? I am getting about 14mpg on highway and around town, when I baby it. The Jeep only has 76,000 miles. Seems like it should get better milage. It's only pushing 1,600rpm at 65mph. Is there something I need to do? Has new plugs and wires. Waiting for warm weather to do the nutter bypass and TFI/motorcraft ignition upgrade. Thanks for the help.

 

[TwistedCU]

Well first of all, the 65 mph on your speedometer is innacurate with 31" tires. You're actual speed is higher than that. That's easily fixable with a new speedo gear:
Chart:
http://www.iaxs.net/~leif/LPsJeepTJ/TiresSpeedoRims/index.html#Anchor-SpeedoGear
BUY:
http://www.quadratec.com/products/product_search.php?kw=speedometer+gear&submit=Go!



Secondly, that's a really high gear ratio for 31's. You should have something like 3.73 or 4.10 gears for those 31" tires, but I doubt that is why your fuel economy is suffering, although it probably doesn't help if the Jeep is lacking power at highway speeds.

 

[LRwrnglr]

Thats about what I get on my 88 YJ. I've went through everything on mine and thats still what I ended up with.

LR

 

[Green97TJ]

Doesnt sound unreasonable to me. I dont get much better from my 03 with 3.73's and 31's. And thats with the newer fuel injected engine.

 

[jfrabat]

I get around 17 with my 2.5L 94 YJ on 31's with 4.10 gears...

 

[lah2420]

I get about 13`to 14 with 3.07s, 31s, MC2100, TFI, Nutter.

 

[Megamole]

So what rpm are you running at 60, or 65mph? I run about 1,500rpm is that low?

 

[jfrabat]

I run about 2,300~2,500 if I remember correctly... I'll verify it tonight, though.

Felipe

 

[lah2420]

Mine runs about 1600 around 60 mph if I remember right. I'll try to check on my way to work tomorrow to verify. ---If my imaginary mind remembers to tell me to pay attention.

 

[jfrabat]

I run about 2,300~2,500 if I remember correctly... I'll verify it tonight, though.

Felipe

I checked; mine says 2,400 RPMs when the needle hits 60 mph.... BUUUUT, I have not adjusted my speedo, so I am probably doing something more like 64 or 65 at that point. So I am guessing 2,300 is about right.

Felipe

 

[JEEPFIRFGHTR]

My new rubicon gets 210miles on a 16 gallon tank. The best ever. usually I get about 195.

 

[Megamole]

Did the Nutter bypass this today, what a big improvement in the way the engine runs and idles. This should help the milage a bit. Still waiting to do the ignition upgrade.

 

[bad ass yj]

Did the Nutter bypass this today, .

Im new to the whole thing, what is the Nutter bypass? i just bought a 90 yj and trying to learn what todo on it. thanks

(sorry for hijacking your thread)

 

[currupt4130]

...

 

[Megamole]

Bad ass do a search in the cj,yj,tj forum for nutter bypass. You will find all you could ever want to know about the nutter bypass and how it can help out your carbd 4.2L