When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Many good points I have a 4 1/2" lift with quite a bit of air drag, I also carry quite a bit of extra weight in the cargo area recovery gear, tools, safety, large first aid anyway its full.
Before I did most of this I bought it with a poorly done 3" lift and 31x10:50x15's and it got about 12 mpg empty.
When I finished (see pic) it has 33x12:50x15's with 3.55 gears and the mpg was 8.7-9. I upgraded gears and lockers to 4.56's and my mpg increased to15-18 with the gear alone. IMHO one of the single best upgrades I have made to my XJ are the gears and lockers done at the same time and the locker install is free with gears.
Others may disagree and YMMV but I know what they did for me on and off road
Not to be a negative nancy here but nobody mentioned that we drive boxes with wheels. Nothing aerodynamic about it. If you need mileage then grab a small four banger for your commute. My mileage sucks but I don't worry about it because it's the nature of the beast with what we have. All three of my jeeps are kept in tip top running order. I see tons of posts about increasing mileage and it just gets redundant. Yes you can do little things for minor improvement in mpg, but over all if you are trying to get 25mpg out of a Cherokee your thinking is too far out there. Do your maintenance, use quality parts, keep your foot out of it is the best your gonna do. Like I stated I'm not trying to be negative just realistic.
Click on the "pink link" in my signature below and do Tips 1,3,4, and 5.
Make sure your odometer reads correctly.
I would replace the O2 sensor with an NTK brand and clean your throttle body. Tip 11.
Good advice here. To me your idle seems too low, not what the issue is and don't have any parts recommendations. I don't think it will be one magic bullet just a lot of little things that add up.
Not to be a negative nancy here but nobody mentioned that we drive boxes with wheels. Nothing aerodynamic about it. If you need mileage then grab a small four banger for your commute. My mileage sucks but I don't worry about it because it's the nature of the beast with what we have.
This isn't helpful at all, and I HATE it when people make this argument. This isn't some guy who is getting 20 MPG wondering what he can do to get an unrealistic 30. This is a guy who is getting 11 when he could be getting 17. He's missing 20-40% of the efficiency he could have. That matters, and there's no reason for him to feel as if he shouldn't find-out why he's missing those MPG's.
Yes, we have one of the least aerodynamic vehicles on the road today, but that doesn't mean we shouldn't try to keep our fuel efficiency as "healthy" as possible. Do you shame people for trying to squeeze extra power or torque or suspension travel or tire size out of their XJ, too? Probably not, so why do you feel that MPG concerns should be taboo?
I average 19 MPG. I get over 22 MPG on the highway, and I have a number of inexpensive mods on the way that WILL increase those numbers further (details about my XJ can be found at http://www.jeepforum.com/forum/f177/...hread-2525690/). I won't be surprised if I hit 25 MPG on the highway someday; it's not my goal, but it wouldn't surprise me. I've seen a 2wd 5-speed 4 cyl XJ get nearly 30 MPG (quite a few mods, though). We CAN get decent to good mileage, so please stop shaming people for pursuing it.
This isn't helpful at all, and I HATE it when people make this argument. This isn't some guy who is getting 20 MPG wondering what he can do to get an unrealistic 30. This is a guy who is getting 11 when he could be getting 17. He's missing 20-40% of the efficiency he could have. That matters, and there's no reason for him to feel as if he shouldn't find-out why he's missing those MPG's.
Yes, we have one of the least aerodynamic vehicles on the road today, but that doesn't mean we shouldn't try to keep our fuel efficiency as "healthy" as possible. Do you shame people for trying to squeeze extra power or torque or suspension travel or tire size out of their XJ, too? Probably not, so why do you feel that MPG concerns should be taboo?
I average 19 MPG. I get over 22 MPG on the highway, and I have a number of inexpensive mods on the way that WILL increase those numbers further (details about my XJ can be found at http://www.jeepforum.com/forum/f177/...hread-2525690/). I won't be surprised if I hit 25 MPG on the highway someday; it's not my goal, but it wouldn't surprise me. I've seen a 2wd 5-speed 4 cyl XJ get nearly 30 MPG (quite a few mods, though). We CAN get decent to good mileage, so please stop shaming people for pursuing it.
Well, yes and no on MSCHI772. You don't drive a 4.0 Cherokee for the great gas mileage-You drive it for the 4x4 capability, snow traction, mud traction etc. If you keep it close to stock ride height, tires etc, then you would expect stock gas mileage. EPA posted mileage is 15 City, 20 Hwy with combined 17 MPG.
Guys post all sorts of 1 tank full numbers where they changed to platinum spark plugs and got 5 more MPG. Not going to happen.
The OP says he's getting 11.5 MPG. He doesn't say how he came up with that figure. Maybe it is 12 MPG or maybe that's really 15, I don't know how he did it, how he figured it was 11.5 MPG, did he average 3 fill-ups, top-offs, full tanks on city driving/highway driving, were they US gallons, Imperial gallons, is he driving up hills, on flat terrain, on the highway, mixed etc etc.
Easy driving saves more gas. Oil changes, clean air filters, good O2 sensors, using stock tires, keeping tires inflated to the right pressure, not carrying a spare or 100 lbs of sand bags for traction etc will all help.
Anyone who expects to get 30 MPG is going to be disappointed but if you get 15 one day and 20 the next you may not be calculating the mileage correctly as far as my experience goes. My 1.8L Toyota only gets 32 MPG HWY. Saying a 4.0 is going to get 22+ is really stretching it since they didn't get that from the factory. A manual transmission only helps the city driving numbers. Highway numbers will be very close to a 4-Spd Auto. Even the 2.1L , 5-SPD, Turbo Diesel only shows 26 MPG HWY on the fueleconomy.gov website. 2WD versions weren't much different either.
I'm all for helping but we sometimes have to take the information given with a grain of salt. Remember "Your results may vary" and "Results not typical" are added to all those weight lost commercials!
70% overland 30% city all flat no hills.
no offroad
no hard acceleration as I want to calculate as good mpg as possible
full tank 100km later next fill up, that 5 times and calculated...11.5 mpg or 21litre for 100km
I realized an issue with my coolant bottle cap....some air is coming out. what could effect from this?
Get a Volvo cap. Napa number 703-1396.
You've done a good job calculating MPGs and have taken a good approach.
I think most of us are used to sketchy figures from folks with less than great mathematical and diagnostic skills. Sorry if you got lumped into that category.
Which Bosch plugs did you use? I'm not a big fan of them, especially the gimmicky ones.
70% overland 30% city all flat no hills.
no offroad
no hard acceleration as I want to calculate as good mpg as possible
full tank 100km later next fill up, that 5 times and calculated...11.5 mpg or 21litre for 100km
I realized an issue with my coolant bottle cap....some air is coming out. what could effect from this?
Great-Thanks for clearing it up. 21L is 5.55 US Gallons but 100km is only 62 miles so you may wish to extend that a bit but it certainly seems poor. If I was doing it, I would run as far as I could safely go on the full tank, re-fill to that and then use those results. Doing it 5 times should be about the same if done right.
How new is the Oxygen Sensor? I just changed mine and it has made a difference on mileage too.
Great-Thanks for clearing it up. 21L is 5.55 US Gallons but 100km is only 62 miles so you may wish to extend that a bit but it certainly seems poor. If I was doing it, I would run as far as I could safely go on the full tank, re-fill to that and then use those results. Doing it 5 times should be about the same if done right.
How new is the Oxygen Sensor? I just changed mine and it has made a difference on mileage too.
ald plugs, some champion ones...look realy old...and the bosch ones i had.
put them in as they came no gap change at all. Or should I? Or other plugs?
@ cruiser54
got the grounds at the engine cleaned up and ordered a new thermostat the 4th time as the ones came aren´t right. It is hard to get the right parts for renix here in germany. every part dealer got parts 1991 on so I ordered in the US. Next will be clearing the throttle and idle air control valve...
Steffen-Those champions look pretty tired. Try shipping from rockauto.com. I checked and it would be $20 to Berlin. They have really the best prices online.
The Bosch 7927 might be closer to Champions. Gap should still be 0.035" or 0.8mm. Your FR 8 HC might be ok. I have only used Bosch Iridium plugs on Toyotas and Mazdas-never on the old cars/jeeps.
