Another gas mileage thread - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Engines & Drivetrain > Another gas mileage thread

Labor Day Sale!FS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitFS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 02-06-2011, 09:30 PM   #1
98jeepzj
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2010
Location: selden, NY
Posts: 300
Another gas mileage thread

I know theres probably a million threads out there but no-one can have as bad of gas mileage as me. I have a 98 jeep grand cherokee laredo 4.0 motor, 3.5" lift 31x10.5x15 general grabber AT2s. I literally get 9 MPG. How or why is it so low and is there anyway to get better gasmileage besides chipping it?

98jeepzj is offline   Reply With Quote
Unread 02-06-2011, 09:54 PM   #2
The_Blacksmith
Registered User
1993 XJ Cherokee 
 
Join Date: Mar 2009
Location: New York
Posts: 2,831
9mpg per you doing the math, or staring at your overhead consoul which is completely wrong due to bigger tires?

in my 93 GC 4.0 on 2.5'' lift and 31s my overhead read 9 /10 mpg constantly. Was getting considerably more.
__________________
http://www.jeepforum.com/forum/f11/replacing-floors-xj-pics-1122602/

http://www.jeepforum.com/forum/f11/building-recovery-bumpers-pics-1184330/
The_Blacksmith is offline   Reply With Quote
Unread 02-06-2011, 10:12 PM   #3
Ahrnsbrak14
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2011
Location: owings, MD
Posts: 302
There is a lot you can do to you engine besides a chip to get way better gas milage. here is some of the stuff, get an electric fan, free flowing exhaust(hi flow cat, muff), cold air intake(if you dont go offroading to much), throttle body spacer, change your sparkplugs and wires maybe even your coil. And maybe the easiest of all, make sure your not cruising at 70 mph everywhere you go
Ahrnsbrak14 is offline   Reply With Quote
Unread 02-06-2011, 10:37 PM   #4
98jeepzj
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2010
Location: selden, NY
Posts: 300
I did the math and got 9.3 my overhead said 9.7 so its not far off. I keep the rpms under 2000. And I usually cruise at like 55 to 65. I'm pretty sure my cat is hallow but I'm not sure. Its old and that could noone ever hallowed it out but I know its all messed up. (But no codes)
98jeepzj is offline   Reply With Quote
Unread 02-06-2011, 10:46 PM   #5
98jeepzj
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2010
Location: selden, NY
Posts: 300
I'm pretty plugs and wires. They look pretty new and I doubt it about 2 months ago
98jeepzj is offline   Reply With Quote
Unread 02-06-2011, 10:51 PM   #6
98jeepzj
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2010
Location: selden, NY
Posts: 300
I'm pretty sure it has *
98jeepzj is offline   Reply With Quote
Unread 02-06-2011, 10:55 PM   #7
RogueSpear2023
Registered User
2003 TJ Wrangler 
 
Join Date: Jun 2008
Location: Fargo, ND
Posts: 6,950
Quote:
Originally Posted by Ahrnsbrak14 View Post
There is a lot you can do to you engine besides a chip to get way better gas milage. here is some of the stuff, get an electric fan, free flowing exhaust(hi flow cat, muff), cold air intake(if you dont go offroading to much), throttle body spacer, change your sparkplugs and wires maybe even your coil. And maybe the easiest of all, make sure your not cruising at 70 mph everywhere you go
The throttle body spacer does nothing for mileage or power, they do work in a carbed motor, but in EFI they do absolutely nothing, just gimmick to make people spend money, just like the tornado thing for you intake will increase mileage it again does nothing.

CAI will help very little, same with the exhaust both waster more money the get you mileage back.

I would definatly look at giving your Jeep a tune up, plugs wires, if you haven't changed you plugs in the last 50K it's time. After that just driving nice easy on throttle and brake will help more than anything else.
__________________
Max

2003 Jeep Wrangler Rubicon
4.0L, 42RLE, Dual Tops, Full Doors, JKS Front Disconnects, Cragar Soft 8 Black Wheels, 33x12.5x15 Goodyear Duratracs, .75" Front Coil Spacers, Bushwacker 6" Flat Fender Flares, Skid Row Steering Box Skid, LubeLockers, Rubicon Locker Mod, OBA, Cobra 19 Ultra III CB, 3' Firestik, Rough Country 2.2 Steering Stabilizer, RC 1.25" BL, RC 1" MML, RC Grab Handles, Fog Lamp Bent Pin Mod, 4" Apline S Series Speakers, Kenwood Excelon 6.5" Speakers, 6.5" JL Audio 6W3V3 Subwoofer (in center console) w/MTX Thunder 202 amp, IPF H4 Headlight Housing, Sliverstar H4 bulbs.



TJ Tech Boot Camp
TJ Specs

"Buying a jeep and not taking it off road, is like buying a dragster and never taking it to the track"
RogueSpear2023 is offline   Reply With Quote
Unread 02-06-2011, 11:37 PM   #8
98jeepzj
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2010
Location: selden, NY
Posts: 300
Quote:
Originally Posted by RogueSpear2023 View Post
The throttle body spacer does nothing for mileage or power, they do work in a carbed motor, but in EFI they do absolutely nothing, just gimmick to make people spend money, just like the tornado thing for you intake will increase mileage it again does nothing.

CAI will help very little, same with the exhaust both waster more money the get you mileage back.

I would definatly look at giving your Jeep a tune up, plugs wires, if you haven't changed you plugs in the last 50K it's time. After that just driving nice easy on throttle and brake will help more than anything else.
Yeah like I said I try to jkeep it under 2000 rpms. I will have to recheck the plugs and wires. Even before the lift I only got 12- 14 MPG so I can't figure out why its so low. And I just hit 100k miles.
Could the cat being all messed up and there being a exhaust leak at the heads and in the muffler be a cause?
98jeepzj is offline   Reply With Quote
Unread 02-07-2011, 11:07 AM   #9
Ahrnsbrak14
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2011
Location: owings, MD
Posts: 302
Quote:
Originally Posted by RogueSpear2023 View Post
The throttle body spacer does nothing for mileage or power, they do work in a carbed motor, but in EFI they do absolutely nothing, just gimmick to make people spend money, just like the tornado thing for you intake will increase mileage it again does nothing.

CAI will help very little, same with the exhaust both waster more money the get you mileage back.

I would definatly look at giving your Jeep a tune up, plugs wires, if you haven't changed you plugs in the last 50K it's time. After that just driving nice easy on throttle and brake will help more than anything else.
I used to think the spacer didn't do sh*t but I installed one and it pushed my mpg up from 15-18. Cai and exhaust will do you good. They can give you 2 or 3 mpg each witch ads up fast. And can be cheap to do. You can just simply take out your cants and muff for free for example.
Ahrnsbrak14 is offline   Reply With Quote
Unread 02-07-2011, 11:15 AM   #10
The_Blacksmith
Registered User
1993 XJ Cherokee 
 
Join Date: Mar 2009
Location: New York
Posts: 2,831
Quote:
Originally Posted by 98jeepzj View Post
I did the math and got 9.3 my overhead said 9.7 so its not far off. I keep the rpms under 2000. And I usually cruise at like 55 to 65. I'm pretty sure my cat is hallow but I'm not sure. Its old and that could noone ever hallowed it out but I know its all messed up. (But no codes)
you did the math wrong.

the overhead consoul is off by the exact percent the tires are larger than stock.

for reference my overhead consoul was 4 + mpg off from 31s down to 215 70s

your tach and speedo are also off too, for driving reference.
__________________
http://www.jeepforum.com/forum/f11/replacing-floors-xj-pics-1122602/

http://www.jeepforum.com/forum/f11/building-recovery-bumpers-pics-1184330/
The_Blacksmith is offline   Reply With Quote
Unread 02-07-2011, 11:17 AM   #11
The_Blacksmith
Registered User
1993 XJ Cherokee 
 
Join Date: Mar 2009
Location: New York
Posts: 2,831
http://www.tacomaworld.com/forum/tirecalc.php

type in 215 70 15 as stock and 31 x10.5 15

15.4% difference in diameter

- 13.3% in rpm ect ect

your speedo is off 9.22 mph @60 to the positive side.
__________________
http://www.jeepforum.com/forum/f11/replacing-floors-xj-pics-1122602/

http://www.jeepforum.com/forum/f11/building-recovery-bumpers-pics-1184330/
The_Blacksmith is offline   Reply With Quote
Unread 02-07-2011, 11:51 AM   #12
Ahrnsbrak14
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2011
Location: owings, MD
Posts: 302
Quote:
Originally Posted by The_Blacksmith View Post
you did the math wrong.

the overhead consoul is off by the exact percent the tires are larger than stock.

for reference my overhead consoul was 4 + mpg off from 31s down to 215 70s

your tach and speedo are also off too, for driving reference.
Is that something that is easy to fix? Do you have to by a chip to change that?
Ahrnsbrak14 is offline   Reply With Quote
Unread 02-07-2011, 11:58 AM   #13
Ahrnsbrak14
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2011
Location: owings, MD
Posts: 302
Quote:
Originally Posted by The_Blacksmith View Post
you did the math wrong.

the overhead consoul is off by the exact percent the tires are larger than stock.

for reference my overhead consoul was 4 + mpg off from 31s down to 215 70s

your tach and speedo are also off too, for driving reference.

Is that something that is easy to fix? Do you have to by a chip to change that? The rpms and speedo..
Ahrnsbrak14 is offline   Reply With Quote
Unread 02-07-2011, 03:59 PM   #14
98jeepzj
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2010
Location: selden, NY
Posts: 300
its not off, ive driven threw school zones with the how fast you are going signs, its the exact same on the sign as it is on my dash.
98jeepzj is offline   Reply With Quote
Unread 02-07-2011, 04:38 PM   #15
Ahrnsbrak14
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2011
Location: owings, MD
Posts: 302
Well your tires are not huge and supper tready so I'm not surprised.. But double check your math and try investing in a tune up and perhaps an electric fan.
Ahrnsbrak14 is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.