Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

Bad gas mileage

Thread Tools
 
Search this Thread
 
Old 07-10-2014, 06:44 PM
  #1  
Newbie
Thread Starter
 
tjcustomranger's Avatar
 
Join Date: Mar 2014
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default Bad gas mileage

My 85 is getting about 13 highway.... What could be causing that? Should be getting better than 13
Old 07-10-2014, 07:02 PM
  #2  
Member
 
XJC1's Avatar
 
Join Date: Jul 2014
Location: Central Colorado
Posts: 143
Likes: 0
Received 0 Likes on 0 Posts
Year: 2000
Model: Cherokee
Engine: 4.0 H.O soon 4.7
Default

Spark plugs, driving in a hot day. .. I've had a crappy battery effect my mpg I would assume due to weak energy. How is your alignment and tires. What type of gas do you use.
Old 07-10-2014, 07:14 PM
  #3  
Seasoned Member
 
timberwolf's Avatar
 
Join Date: Feb 2012
Location: PA
Posts: 307
Likes: 0
Received 0 Likes on 0 Posts
Year: 1996
Model: Cherokee
Engine: 4.0
Default

what did it get before?
did it drop suddenly or has been getting worse?
if you have the carb'd 2.8 I wouldn't expect more than 15-16mpg
Old 07-10-2014, 07:36 PM
  #4  
Newbie
Thread Starter
 
tjcustomranger's Avatar
 
Join Date: Mar 2014
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Slightly larger than stock tires. Battery needs replaced soon.
Pretty sure it was tuned up about 800 miles ago. Alignment and tires were done 600 miles ago.
It has the 2.5 amc. It seems like its getting worse and the weather has been high 80's to mid 90's. I'm running 89 in it right now. I drive 52 miles a day. 26 in the morni g and 26 in afternoon. Have the 5 speed and do on average 60-65. Rpm is about 2500-3000.
Old 07-10-2014, 08:07 PM
  #5  
CF Veteran
 
BlueRidgeMark's Avatar
 
Join Date: May 2012
Location: Lost in the wilds of Virginia
Posts: 7,964
Received 952 Likes on 767 Posts
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Default

Basic tune-up items, bad 02 sensor, vacuum leak. There can be a lot of reasons.
Old 07-10-2014, 08:27 PM
  #6  
Newbie
Thread Starter
 
tjcustomranger's Avatar
 
Join Date: Mar 2014
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Would it act up in a way if it was o2 sensor? I don't think there are any vacuum leaks.
Old 07-10-2014, 08:27 PM
  #7  
Newbie
Thread Starter
 
tjcustomranger's Avatar
 
Join Date: Mar 2014
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

Where is the o2 sensor located?
Old 07-10-2014, 11:32 PM
  #8  
Seasoned Member
 
zeecherokeeman's Avatar
 
Join Date: Jul 2012
Location: maryland
Posts: 415
Likes: 0
Received 1 Like on 1 Post
Year: 2 Door 1996
Model: Cherokee
Engine: 4.0 L H.O.
Default

02 sensor is located on the down pipe exhaust.Before the Cat.converter.You can have it tested to see if its bad.Also clean throttle body,clean I.a.t.Clean your battery terminals if there dirty.Get it tested at local auto store to see if there is any codes.They might do it for free not sure..Good luck!!
Old 07-11-2014, 06:56 AM
  #9  
Member
 
Epk5150's Avatar
 
Join Date: Mar 2014
Location: Virginia Beach, VA
Posts: 197
Likes: 0
Received 0 Likes on 0 Posts
Year: 1996
Model: Cherokee
Engine: 4.0L
Default

What is I.a.t.? This may be a stupid question but how do you clean the throttle body?
Old 07-11-2014, 07:29 AM
  #10  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,872
Received 1,526 Likes on 1,238 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

85 four cylinder is carbureted...........

See if the carb itself is loose between it's base and main body.
Old 07-11-2014, 11:54 AM
  #11  
Senior Member
 
Pelican's Avatar
 
Join Date: Mar 2013
Location: Texas
Posts: 691
Likes: 0
Received 2 Likes on 1 Post
Year: 1993
Model: Cherokee
Engine: 4.0L
Default

Not going to get a lot of codes on an '85 2.5.
Old 07-11-2014, 10:01 PM
  #12  
Seasoned Member
 
zeecherokeeman's Avatar
 
Join Date: Jul 2012
Location: maryland
Posts: 415
Likes: 0
Received 1 Like on 1 Post
Year: 2 Door 1996
Model: Cherokee
Engine: 4.0 L H.O.
Default

ohh yeah..I realized it was carb after I posted..You can clean carb with Carb cleaner and you probably don't have I.a.t. sorry..
Old 07-12-2014, 06:51 AM
  #13  
CF Veteran
 
BlueRidgeMark's Avatar
 
Join Date: May 2012
Location: Lost in the wilds of Virginia
Posts: 7,964
Received 952 Likes on 767 Posts
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by tjcustomranger
Would it act up in a way if it was o2 sensor?
It will run crazy rich. Stomp on it and you'll get black smoke from the exhaust.

Originally Posted by tjcustomranger
I don't think there are any vacuum leaks.

Why do you think that? Have you done any testing? Or is it just a 'feeling' you have?
Old 07-12-2014, 08:36 AM
  #14  
CF Veteran
 
EZEARL's Avatar
 
Join Date: Aug 2009
Location: WV
Posts: 5,676
Received 298 Likes on 253 Posts
Year: '96
Model: Cherokee
Default

Could be the carb needs adjusted or possibly a rebuild. Get it running to operating temp. Try adjusting the carb if there is a way to. Some have the adjustments plugged (we use to drill them out). If there's a way to adjust it but it won't respond it's time for a rebuild. Or with it running and the air filter off look in the carb and see if it's dripping gas at idle. If so it's time for a rebuild.
Old 07-12-2014, 09:37 AM
  #15  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,872
Received 1,526 Likes on 1,238 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by BlueRidgeMark
It will run crazy rich. Stomp on it and you'll get black smoke from the exhaust.




Why do you think that? Have you done any testing? Or is it just a 'feeling' you have?
My favorite method of diagnosing involves no hands-on testing.
I much prefer contacting the spirit world. A tried and true method is to get a group of like-minded folks together, hold hands in a circle around the vehicle, and sign Kum-ba-ya.


Quick Reply: Bad gas mileage



All times are GMT -5. The time now is 05:06 AM.