2000 XJ Low Idle Question

[Better_than_Tom]

I have a 2000 xj and it idles around 500 rpm. It seems to idle smooth but I suspect this is low. Does anyone know what the idle should be and is there any kind of adjustment?

My air filter is clean, spark plugs are new and properly gapped and the xj has done this as long as I have owned it.

 

[Tim_MN]

Is the low idle a problem, or does it cause stalling ?

The Idle Air Controller (IAC) and the engine computer (ECU) control idle speed, so there is no adjustment.

 

[birchlakeXJ]

I'd verify it just to be sure your tach isn't off.

And if the lower idle is creating no issues (is there any stalling, etc because of it?), I would leave well enough alone and not chase it.

On older vehicles, it's a good strategy to "choose your battles".

 

[Original_MudButt]

The idle should be around 800 rpm as I recall...

 

[Better_than_Tom]

For the most part the jeep runs fine. I have had it stall just a couple times when it is cold at night and it also always stall if I turn the wheel all the way to either direction while I'm going 2mph or less, is that normal? Is there anyway to test or clean the idle air controller?

 

[Pz10420]

Any stalling is not normal IMO. Unless your 16 and just learning to drive stick.

 

[Pz10420]

I'm sure someone on here can tell u how to check ur iac better than me. But I would also make sure your whole throttle body and intake are not too gummed up.

 

[Better_than_Tom]

Ok thanks fro the pointer I'll prolly try to run some kind of cleaner through the fuel system to be safe and hopefully someone knows how to check the IAC.

 

[PahlMc]

I have a 2001 auto with the exact same low idle. No problems yet but it is low. I ran injector cleaner thru mine and changes the PCV equivalent with no change. Until its an issue, I'm going to ignore it.

 

[birchlakeXJ]

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

Reinstall IAC and check idle quality

 

[Better_than_Tom]

Thanks...Ill give it a try!!