dear all,

hello this is my first post , i just got myself a grand cherokee limited 2001 model with 70000 mile on the clock and in very good condition and with clean car fax history.

however i want to check with you please regarding the fuel consumption because i think its high. i have the v6 engine 4.0 litres.

the computer is reading like this :

these figures are with the AC on.

from 21.9 l / 100 kilometers to 27.5l/ 100 kilometers !!!!!!!!!

when i put 17.5 liters of fuel the computer reads 92 kilometers to empty and then again it drop down so fast to 89 and then again 90 and 87 and so on. and the actual kilometers i did with the 17.5 litres in the end was 50.8 !!!!!!!!??? and then the light was on nd i had to put fuel again.

is the above normal???

i changed the air filter and i cleaned the throttle body and i did full maintenance just before i bought the car. i even cleaned the injectors


plz let me know if the above is ok and if not what shall i do to fix it ?

thanks

 

You're going to have to dumb it down for us non metric folks. What does that work out to be in miles per gallon?

 

sorry i am in DUBAI UAE and we deal with these numbers but anyway let me give you the numbers in MPG better.

21.9 l / 100 kilometers to 27.5l/ 100 kilometers !!!!!!!!!

MEANS

FROM 13 MPG 10 mpg ??

THANKS

 

Here, let me translate! (I may have too much time on my hands)

At first I thought that I got the math wrong, but after doing it a few times, that's right. Your fuel economy is terrible. It is normal to see a small drop in economy with the A/C on, since the compressor is putting an extra load on the system, but your base value there is quite low. Perhaps you're merely getting poor fuel wherever it is you fill up, or maybe you have a different problem.

EDIT: All that work, I was too slow! My numbers sure look less favorable!

 

thank you for the translating , however i think it should be 10 MPG to 13 MPG as per the webiste that translated my figures

anyway if my fuel consumption is horrible what can i do to fix it? the engine runs very well and my oil pressure is perfect and the car has lots of power. and everything seems fine? the engine sound also is very good no lifter ticks and has no smoke at all whatsoever.

what could it be?

thanks

 

Have installed larger tires recently? That will throw your numbers off.

 

yes i installed new wrangler good year tires 255 65 17

the numbers that the computer is showing are really odd , i am really having horible fuel consumption

please tell me what shall i do or what shall i start checking???

thanks

 

I don't think your mileage has changed all that much, it just looks that way becaues the larger tires do not rotate at the same rate per mile as the stock size tires do. You're just recording less distance on the odometer and it is throwing your math off.

 

yes but im not complaining about the tire size , i am having a real issue here that is my fuel cosumption


what shall i start to check to improve it where should i start or what shall i do

here is the things i have done so far:
new spark plugs mopar
new air filter
new oil and filter ( engine)
cleaned the injectors and cleaned the throttle body
new tires


what esle should i do ? maybe the computer is faulty thorwing out crazy numbers??? but i realy go to the fuel pump everyday now its crazy like this .

 

and if my computer is off how can i reset it to read the new tires or to give me the actual mileage?

thanks

 

Crazy numbers because of the larger tire size. You may be able to change the gear on the vehicle speed sensor to help the speedometer and odometer read correctly.

 

can you please help me and answer me in full answer , because as you can see iam noob here.

i just saw the tires now and its goodwear wrangler 255/60r17 , are they bigger than the stock? and do they really make this difference? what else can i check please

and what do you mean by changing the gear sensor . how ?

im waiting for your help plz

thanks

 

The stock tire size for your 95 ZJ is 235/75/15, you have 255/65/17s on your Jeep now. Those tires are wider and taller, because they are taller, it takes less revolutions for the tire to go the same distance as the original sized tire. That will cause the tripmeter to read less of a distance and make you think you have driven less distance than you have really driven.
At the rear of the transfer case on the left side, there is the vehicle speed sensor. On the end of that sensor is a gear that can be changed to correct the speedometer/tripmeter/odometer reading. Once you have the speedo reading the correct speed, you will find that you fuel consumption has not changed much at all.
http://www.miata.net/garage/tirecalc.html use this site to detrmine difference between the rolling distance of the stock size tires vs the new size you're running.

Well, I just used the site and found not much of a difference at all in the rolling distance. 698 rev per mile for the original tire vs 671 per mile for the new tire size.
Are the new wheels and tires any heavier than the originals?

 

who said that i have zj and who said its 95 model??????

i have a 2001 grand cherokee limited and no the tires are not heavier

do you have any pics of the location of this speed sensor please?
thanks


also my new tires are 255/60r17 and not 65
thx

 

You know I'm real sure where I got the wrong year, it's been a long sleepy day. I don't have any pics of the speed sensor, but I don't think that is the problem anyway. I'm not real sure what is causing the high fuel cunsumption issue. Is the check engine light on? I hate to have you to just start throwing parts at your Jeep, but maybe change the upstream O2 sensor.