4 Banger Fuel effeciency

[]lllllll[] · #1 (**permalink**) 07-20-2003, 08:00 PM

I have a 91 2.5 5 speed and i get about 13 mpg. Is there any way to get more fuel effecient? I shift on average at 2500. I do alot of highway driving (70 mph) also, could this be the problem? I hear some people get 20's in 4 bangers. I'm running 31's with stock everything. Does anyone know whats up?

James[addsig]

beattie1175 · #2 (**permalink**) 07-20-2003, 08:00 PM

Hi James and welcome. I have a '94 YJ with the 2.5L also. I get about 16 around town and 15 on the hiway. Mine also is pretty much stock with a 3" body lift and 31" tires. You're working the engine pretty hard with the stock gearing, so I wouldn't expect much more than that. [addsig]

jterp · #3 (**permalink**) 07-20-2003, 08:00 PM

I believe the 2.5 L came with a 4.10 rear end -- pretty tough to get good gas mileage with that steep of a gear. The 31's should help though. How is your exhaust? A clogged muffler or cat can hinder gas mileage. Is yours fuel injected? (I'm not sure when the switch was made). If so you might try adding a fuel injector cleaner -- a bad fuel injector can kill MPG.[addsig]

ZBTstang · #4 (**permalink**) 07-20-2003, 08:00 PM

wow there []IIIIII[] it must really suck for you to sign in unless you have the "remember me" button checked[addsig]

Jeepster05 · #5 (**permalink**) 07-20-2003, 08:00 PM

Haha good point. The 91 YJs are fuel injected my dumb a$$ got a 90 so I'm screwed with the carb which is the reason its in the shop right now. :-x [addsig]

Bounty__Hunter · #6 (**permalink**) 07-20-2003, 08:00 PM

If you slow down on the top end, you're mileage will improve a couple of points. Rest of it is mechanical, need a tune-up or repair a vacuum leak. Make sure the PCV system is working properly and there are no dry-rotted/collapsed vacuum lines.[addsig]

JeepGirl · #7 (**permalink**) 07-20-2003, 08:00 PM

What gear ratios should a YJ 2.5L get for 33" tires? [addsig]

Tug-n-pull · #8 (**permalink**) 07-20-2003, 08:00 PM

87 YJ 5 speed 4 banger does really well for me as far as MPG goes I get 16 town 18 hwy and I drive the little guy. The K&N, Flowmaster and lack of a cat help alot I am sure. I plan to loose some mileage as I lift and grow my tire size here pretty soon. 13 MPG is just to low. Good Luck tug[addsig]

[]lllllll[] · #9 (**permalink**) 07-20-2003, 08:00 PM

I've added fuel injector cleaner and it helped improve acelleration a little, but what if one of my injectors are bad? how can i tell if i need a new one? I've done away with my cat but i'm not sure if my muffler is clogged or not. how can i tell if it is clogged? I have about 4 vacumm lines and they are allright. Thanks for helping me out here,

James[addsig]

jterp · #10 (**permalink**) 07-20-2003, 08:00 PM

If a fuel injector is bad you would feel a noticeable loss of power-- your engine would miss and sputter a lot. When was your muffler installed? Is it a stock muffler or an aftermarket? From my experience it seems that you don't get more than 6 or 7 years out of a stock jeep muffler. How does it sound? If it's making a lot of noise then chances are its bad. Regardless if it's bad or not, installation of a low restriction muffler will improve gas mileage. Hope this helps.
[addsig]

[]lllllll[] · #11 (**permalink**) 07-20-2003, 08:00 PM

Are there any special markings on the stock muffler that would tell me that it is stock? It does make alot of noise, but it sounds good.
It only stutters for a little bit when it is warming up, so i dont think it could be an injector. Thanks, jterp[addsig]

JE420EP · #12 (**permalink**) 07-20-2003, 08:00 PM

I have 4.88 with 33's and i get good mileage. It is a lot better then when i had 31's and 4.10.[addsig]