XJwonders

What else is there to do a tune up on a 99 xj?


I got new air filter, oil and filter, spark plugs, wires, cap and rotor, topped off coolant, wipers, master cylinder, and power steering.I don't know what else to replace as part of preventive Maintenace tune up.

Cherokeekid4x4

Fuel filter. Diff fluid changes. Grease up everything. Wait are you just talking about maintnence on the motor? Lol

XJwonders

I was talking about motor but it is always better to do tune up on entire vehicle lol so yes your suggestions is very welcome.

Where is the fuel filter and what oil for differentials?

Cherokeekid4x4

Lol oh gotcha. Fuel filter is by the gas,tank on the drivers side. Look under and you'll see it. It's fairly easy to replace. And not sure ill let you know on the oil when I do mine this weekend if no one else answers that lol. I think you got the motor covered. Good job.

tjwalker

*The fuel filter on a 99 is inside of the gas tank and part of the "fuel pump assembly". It is generally not serviced until symptoms and testing point to a fuel delivery issue and then it is best to replace the entire assembly. So don't worry about replacing the filter when you perform a tuneup.

*Don't forget about your serpentine belt. Inspect it and replace if necessary. I replace mine every 60k.

*How old are your cooling system hoses? Thermostat?

*Fluids are the lifeblood of the vehicle. They need to be changed out periodically. Get a service manual and follow it.

*The throttle body and idle air control can get carboned up over time. If you've never done this, I'd consider doing so.
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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

XJwonders

Wow that's an excellent response. I agree. It should be on the list of every tune up somebody do when they buy a xj.

How often do u think we should clean the IAC sensor, and throttle body.

Cherokeekid4x4

Oh yikes missed that yours was a 99 sorry haha

I ARE EL1TE

I believe you use 80W-90 gear oil for the diffs. Also, you can change your tranny and t case fluids. And maybe grease the u-joints idf they have the zerk fitting on them

98_XJ Sport

I used 75W90 for my differentials.

XJwonders

I have a SYE kit waiting to be installed. What part number for moog u joints I need to get?

RTorrez1

Since you will be under the hood for awhile you may as well clean all of your grounding point and not just the battery cables but all of them. This will help keep your charging system running better.

XJwonders

I just upgraded the battery cables with number two welding cable, it's all clean now

RTorrez1

Did you also clean all of the other grounds? Such as the one at the oil dipstick, Rear of the head to the firewall, the ones at the alt to the coil and the one from the battery to the fender well. Also the connection to the starter. Just because they look clean doesn't mean that they are. And any of those can cause some strange electrical problem, Not that you have any but it is a good maintenance item

XJwonders

I only cleaned those spots that I took the wires off to upgrade the wires. I don't think there was a grounding point at oil dipstick, the battery cable was bolted on the block just forward of the distributor right under the ac compressor.

Is there a ground on dipstick too?