Stephen102938

Hello, I have a 97 Cherokee, what kind of gas milage are you guys getting? I have a magnaflow high performance muffler and a high flow air filter. I'm getting 13 mpg city, any good ways to improve it? All help would be appreciated. And no, I do not accelerate fast and I do not drive it hard.
-Stephen.

black2000xj

2000 jeep cherokee classic

i get about 275-280 to a tank, do the math, 17 mpg, i just replaced the o2 sensors, changed diff fluid and transfer case fluid, and trans fluid, and reset the ecu

hoping it will get closer to 300 miles/tank

tips:
a good tuneup (everything)
change fluids
clean your throttle body
replace o2 sensors
reset ecu

good luck

Spunkmeyer

Some people swap out their fuel injectors for ones out of other vehicles, such as a Dodge Neon. Do a search on this forum and you'll find a ton of threads about it.

One thing you could do right now is buy some Seafoam to clean your existing injectors; just follow the directions on the can. It's available in many auto parts places. You can Google "seafoam" and see what it looks like so you recognize it on the shelf quicker.

justjake

99+ intake manifold, neon injectors, intake, high flow cat all of those would help.

Stephen102938

Thanks man. How much and how hard was it for the o2 sensors? And how do u reset the ecu?
-Stephen

Stephen102938

Thanks, I have heard good things about sea foam but never tried it. Anything else I should know about it?

1996XJSport

Is everything else on the XJ you're driving stock? If it is, you shouldn't be getting that mileage. The "high flow air filter" may be your problem because of your PCM adjusting the mix to run richer with the increased air intake. There are a few simple ways to get better fuel economy. Go buy some Fuel injector cleaner and run it in your gas tank, you can change your spark plugs, Clean out your throttle body with throttle body cleaner, make sure all of your tires are aired to the maximum PSI (not always recommended but it does work). I have heard of modifications of moving the sensor on your intake manifold directly to the air box, also you can do a neon injector swap. Also there is a driving technique that I use when no one is behind me called "hypermiling". What you do is you brake before a red light and keep rolling toward it till it turns green so you don't have to come to a complete stop and accellerate. I've gained a couple mpg's just by doing it. Also, keep your idling to a minimum and keep your shift points down. If you're feathering the pedal, the AW4 will shift at 2100 RPM which is pretty low.


Oh and I forgot to add in what I'm getting in my XJs.
The lifted 1996 XJ on 31s with stock 3.55 gearing, a brand new cat, and a flowmaster 40 series dual exhaust is getting 12 MPG city (when I'm doing normal driving/not trying to get good mileage) I get about 234 Miles to a tank.

My 1992 XJ gets some pretty amazing mileage it is however stock.
Im pulling 17-18 city with it.

black2000xj

yea get some seafoam, pour the whole can into your full tank of gas
do that about every 4-5 tanks

the o2 sensors are pretty easy if they are not rusted in or welded
mine were rusted pretty bad, but some wd40, lite tapping with a hammer and a good breaker bar, they came out

if you do this: get bosch or ntk sensors from napa
dont touch or get the tips of the o2 sensor dirty
reset the ecu

after you replace the o2 sensors
you pull the positive cable off
then the negative
touch them together for 30 seconds
put negative back on
then positive
turn the key on, but dont start your jeep
turn the lights on for 10 seconds
turn them off
turn the key off
let sit for 10 sec

now its reset

(i just did this 2 times in the last couple days, and just started a thread on this b/c i wanted to make sure i did it right)

anyway my mpg is still around the same, but i think it will take a couple tanks to get the mpg up

Stephen102938

Yes all other components are stock. Yes, I do that driving trick also! How could I get my PCM adjusted to the rich mix. The high flow filter is actually a CAI. I should have specified. Thank you, I really appreciate it
-Stephen

Stephen102938

Thanks dude! I will keep that in mind
-Stephen

black2000xj

dont keep it in mind

do it

a little maintenence goes ALONG WAY in a OIIIIIIIO

Stephen102938

O that OllllllllO is clever. Is there anything bad that can happen from resetting the computer?

DocOrng XJ

I was getting about 14mpg, I did a complete tune up:
4 new tires, new plugs, wires, cap & rotor, O2, oil change & filter, radiator flush & thermostat, air filter, brakes and serpentine belt and gas tank injector cleaner, new donut seal at the exhaust pipe/muffler(had a exhaust leak); and now avg about 18mpg

Next on my list is the transfer case, trans filter / fluid and neon injectors and in take manifold (crack in the number 6 down pipe at the collector) - hoping to squeeze out another 1mpg(or better) with that.

I have a oct 86 build (87 model) standard base model xj
Currently with 78862 miles on it. Stock rims.

black2000xj

nothing bad that i know of

the only thing that if you do reset it

your jeeps ecu will be in adaptive learning or something like that

i was told the ecu will adjust to your driving habits for the next 50 driving cycles

so if you do this and you want better mileage

drive like your 95 years old

but remember too

your driving a jeep, not a sports car...they are made to go slow and get you where you need to go

good luck

Stephen102938

Ya I'm a rare 16 year old that always drives like an old person so that won't be a problem for me lol