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02-13-2013, 06:41 PM
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Year: 1996
Model: Cherokee
Engine: 4.0 I-6 High output
Here's how to clean the tb and iac.
Courtesy of TJWalker:
--------------------------------------------------------------------
The Idle Air Control (IAC) is mounted on the back of the throttle body. (front for 87-90) The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.
CLEANING THE JEEP 4.0 IDLE AIR CONTROL
Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)
"Gently" wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged
Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.
Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner
It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled
Courtesy of TJWalker:
--------------------------------------------------------------------
The Idle Air Control (IAC) is mounted on the back of the throttle body. (front for 87-90) The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.
CLEANING THE JEEP 4.0 IDLE AIR CONTROL
Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)
"Gently" wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged
Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.
Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner
It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled
02-13-2013, 06:43 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
02-13-2013, 07:29 PM
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Year: 1996
Model: Cherokee
Engine: 4.0 I-6 High output
02-13-2013, 08:20 PM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
02-13-2013, 08:23 PM
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Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Here is the routing on '91 and prior XJs, the diagram is obviously for YJs but same thing:
If you're going to put a new transfer case in without the vacuum switch you'll need to fix the front axle so it's always engaged. There's some little mod you can do that I think involves moving the shift fork in the passenger-side tube, or you can install a single-piece axle shaft from a later model D30.
As for the dash light... well... most folks' lights don't work anyway... lol But I'm sure there'd be some way to wire a later model switch to or in place of the original vacuum-actuated unit.
Last edited by salad; 02-13-2013 at 08:26 PM.
02-13-2013, 08:26 PM
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Year: 1993 YJ Wrangler
Engine: 4.0 I6
Here is the routing on '91 and prior XJs, the diagram is obviously for YJs but same thing:
If you're going to put a new transfer case in without the vacuum switch you'll need to fix the front axle so it's always engaged. There's some little mod you can do that I think involves moving the shift fork in the passenger-side tube, or you can install a single-piece axle shaft from a later model D30.
As for the dash light... well... most folks' lights don't work anyway... lol
02-13-2013, 08:27 PM
::CF Moderator::
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
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1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Here is the routing on '91 and prior XJs, the diagram is obviously for YJs but same thing:
If you're going to put a new transfer case in without the vacuum switch you'll need to fix the front axle so it's always engaged. There's some little mod you can do that I think involves moving the shift fork in the passenger-side tube, or you can install a single-piece axle shaft from a later model D30.
As for the dash light... well... most folks' lights don't work anyway... lol But I'm sure there'd be some way to wire a later model switch to or in place of the original vacuum-actuated unit.
If you're going to put a new transfer case in without the vacuum switch you'll need to fix the front axle so it's always engaged. There's some little mod you can do that I think involves moving the shift fork in the passenger-side tube, or you can install a single-piece axle shaft from a later model D30.
As for the dash light... well... most folks' lights don't work anyway... lol But I'm sure there'd be some way to wire a later model switch to or in place of the original vacuum-actuated unit.
The "little mod" that takes less than 1/2 hour.
https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/
02-13-2013, 09:52 PM
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Year: 2000
Model: Cherokee
Engine: 4.0
02-13-2013, 11:59 PM
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Year: 1990
Model: Cherokee
Engine: 4.0l 6Cyl
When bleeding the brakes do you leave the resivor cap off or on? Also would it matter if it was bled with it off?
I watched a few videos on youtube about bleeding the system and people kept their resivor lids off. When i did that today on my 88 while pressing the pedal it would shoot fluid up from the booster.
Im confused.
I watched a few videos on youtube about bleeding the system and people kept their resivor lids off. When i did that today on my 88 while pressing the pedal it would shoot fluid up from the booster.
Im confused.
02-14-2013, 12:37 AM
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Year: 1990
Model: Cherokee
Engine: 4.0l 6Cyl
Slowly pushing it. Also what is your prefered method.
Im hearing different things.
I have heard the pusher pushes the pedal 3 times,hold it down, open bleeder till fluid stops squirting out, close bleeder release. Pump 3 more times hold and repeat.
Iv also heard open valve have pushers presses pedal down. When pedal all the way down then close valve and repeat.
I just want to make sure im doing it right. Also i cant find a hose big enough to go around the bleeder so im just letting it squirt till it slows down then im closing it. Repumpong and repeat.
I did the 1st method i said.
Im hearing different things.
I have heard the pusher pushes the pedal 3 times,hold it down, open bleeder till fluid stops squirting out, close bleeder release. Pump 3 more times hold and repeat.
Iv also heard open valve have pushers presses pedal down. When pedal all the way down then close valve and repeat.
I just want to make sure im doing it right. Also i cant find a hose big enough to go around the bleeder so im just letting it squirt till it slows down then im closing it. Repumpong and repeat.
I did the 1st method i said.
02-14-2013, 05:34 AM
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Join Date: Aug 2011
Location: Prescott, Az
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
When bleeding the brakes do you leave the resivor cap off or on? Also would it matter if it was bled with it off?
I watched a few videos on youtube about bleeding the system and people kept their resivor lids off. When i did that today on my 88 while pressing the pedal it would shoot fluid up from the booster.
Im confused.
I watched a few videos on youtube about bleeding the system and people kept their resivor lids off. When i did that today on my 88 while pressing the pedal it would shoot fluid up from the booster.
Im confused.
02-14-2013, 05:35 AM
::CF Moderator::
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes
on
1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Slowly pushing it. Also what is your prefered method.
Im hearing different things.
I have heard the pusher pushes the pedal 3 times,hold it down, open bleeder till fluid stops squirting out, close bleeder release. Pump 3 more times hold and repeat.
Iv also heard open valve have pushers presses pedal down. When pedal all the way down then close valve and repeat.
I just want to make sure im doing it right. Also i cant find a hose big enough to go around the bleeder so im just letting it squirt till it slows down then im closing it. Repumpong and repeat.
I did the 1st method i said.
Im hearing different things.
I have heard the pusher pushes the pedal 3 times,hold it down, open bleeder till fluid stops squirting out, close bleeder release. Pump 3 more times hold and repeat.
Iv also heard open valve have pushers presses pedal down. When pedal all the way down then close valve and repeat.
I just want to make sure im doing it right. Also i cant find a hose big enough to go around the bleeder so im just letting it squirt till it slows down then im closing it. Repumpong and repeat.
I did the 1st method i said.
Pump 3 times, hold, crack the bleeder and close it BEFORE fluid stops coming out. Repeat til no bubbles and clear fluid present.