cherokee gas mileage (lack of)

Reply Subscribe

Thread Tools

Search this Thread

12-10-2008, 07:45 AM

#16

juicy_j

Member

Join Date: Dec 2008

Posts: 164

Likes: 0

Received 0 Likes on 0 Posts

Year: 1998

Model: Cherokee

Engine: 4.0L I6

A fuel system cleaner is a must with these 4.0's. They love to get gunked up and the best way to clean them out is with some fuel system cleaner. I can personally say that it increased my mileage from about 17 up to 22 for one tank and then began to deteriorate back to the 17 range over the next few tanks. It'd probably be a good idea to run some fuel cleaner through their every other tank or so.

Reply Like

12-10-2008, 11:01 AM

#17

BowtieGuy3

CF Veteran

Join Date: Mar 2008

Location: South Side Chicago

Posts: 2,088

Likes: 0

Received 2 Likes on 2 Posts

Year: 1992, 2- 1998 (All 3, 4 Doors)

Model: Cherokee

Engine: 4.0L in all

MAP Sensor Testing

Inspect vacuum lines at MAP sensor and at Throttle Body. Repair as needed.

WHEN TESTING THE MAP SENSOR, ENSURE THAT THE HARNESS WIRES ARE NOT DAMAGED BY THE TEST METER PROBES.

Test the MAP Sensor output voltage at the MAP Sensor connector terminal B (as marked on the sensor body). This is done with the ignition switch ON and the engine OFF. Output voltage should be 4-5 volts.

The voltage should drop to 1.5-2.1 volts with a hot, neutral idle speed condition.

Test engine controller (terminal 5) for the same voltage as described above to verify the wire harness condition. Repair as necessary.

Test MAP Sensor supply voltage at sensor connector (terminal C) with the ignition ON. The voltage should be approximately 5V (+/- 0.5V). 5V (+/- 0.5V) should also be at terminal 6 of the engine controller wire harness connector.

Test the MAP Sensor ground circuit at the sensor connector (terminal A) and the engine controller connector (terminal 4).

Test the MAP Sensor ground circuit at the engine controller connector between terminal 4 and terminal 11 with an ohmmeter. If the ohmmeter indicates an open circuit, inspect for a defective sensor ground connection. This connection is located on the right side of the cylinder block, at the oil dipstick tube mounting stud. If the ground connection is good, replace the engine controller. If terminal 4 has a short circuit to 12V, correct this condition before replacing the engine controller.

As mentioned before, I also use a Lucas Fuel System treatment at every fill-up, and a carb/F.I. cleaner every 10 fill-up's or so.

Last edited by BowtieGuy3; 12-10-2008 at 11:04 AM.

Reply Like

12-10-2008, 11:49 AM

#18

blank87

Seasoned Member

Join Date: Oct 2008

Location: Vail, CO

Posts: 287

Likes: 0

Received 1 Like on 1 Post

Year: 2000

Model: Cherokee

Engine: 4.0

Quote:

Originally Posted by sandstone

How long have you had the K&N CAI on your cherokee? I've been thinking of getting this for a while. So you're happy with it's performance?

I have had it for the last year and yes I am very happy with it.

Reply Like

12-10-2008, 12:20 PM

#19

Jsny1010

Member

Join Date: Oct 2008

Posts: 171

Likes: 0

Received 0 Likes on 0 Posts

Year: 89

Model: Cherokee

Engine: 4.0L

Thanks!

I'll check the MAP today and see what kinda voltage im getting.. yeah i notice that if i treat the fuel it gets better mileage,

anyone ever use seafoam in the fuel? it said it would work but idunno

Reply Like

12-11-2008, 01:52 PM

#20

JFD's 94XJ

Newbie

Join Date: Dec 2008

Posts: 8

Likes: 0

Received 0 Likes on 0 Posts

Year: 1994

Model: Cherokee

Engine: 4.0L HO

Ive had the same intake for almost two years now, and also bought the dry wrap for it. I couldnt tell that much differebce as far as gas mileage, but I like the fact that I can clean it.