My jeeps doing the same thing with the voltmeter, squeaky and it reads lower, it goes up and stops squeaking. Today the CEL came on and before I had a chance to get it to the store to check it, I parked it shut it off and now it won't turn back on. I'll let you know what I find, it may be related or not.

 

Ya please let me know!

 

On a side note with reguards to the distributor suggestion, the 2000 doesn't use a distributor... but it does have a "synchronizer" that drives the cam sensor. The bearing inside can fail and make noise, just like a distributor. They fail pretty regularly on the Ford 3.0 engines, and are a nearly identical part. Typically make more of a "chirping" sound than a squeak noise, for what it's worth.

 

JP, I have a very similar problem with my XJ, same noise as you discribe. I open the cap and revoved a "cover" and I played with the distibutor and it fells like there is some small play on the shaft (I can wigle it a bit left and right ). but I would like to see if you can give me more detail befor I go and buy a new distributor.
gracias.
BTW I live in Bogota Colombia and my Cherokee was built in Venezuela it has dana 44 front and rear, the front being a high pinion 44. 456 gears,auto,4.0 6cyl,

 

Sounds like yours is bad, like my wife's. At our local NAPA auto parts store, a rebuilt distributor was $77, but the core charge was $98! A new distributor (56027028AB) from an Internet Mopar factory parts house was $269 and the Jeep dealer was much more.

You took off the distributor cap, then the rotor. The "cover" you described is a black baffle with a wire coming off it; this is the Hall Effect Sensor that triggers the spark. Disconnect the wire to the sensor. The baffle can be removed by wiggling it upwards out of the slot where the wire protrudes. You should see a whitish plastic disk with a metal fence around half of it now. Grab the distributor shaft an wiggle it side to side. If there is significant side-to-side play (more than just clicking - you can see in move with the naked eye), it's time for a new or rebuilt distributor. 1/16" or less up and down play is normal. Use a flashlight and look for oil residue in the bottom of the distributor's interior. If you find oily residue, that's another sign the distributor is worn out.

I bought a used (120K miles) distributor at a wrecking yard off a 1997 4.0L to rebuild and disassembled it to learn more about how it was designed. I learned quite a bit about the 4.0L engine's distributor over the past week. These distributors fail because the upper bushing burns up due to lack of lubrication.

Today I had my local machinist press the bad upper bushing out, then bought a new stock Oilite bronze bushing to be machined to fit. This is going to be a bitter-sweet project. The DIY rebuild is going to cost more than a rebuilt distributor; after rebuilding and a little reengineering, the revised distributor should last much longer than the original design. The key difference is the original design had a provision for an oil cup to keep the upper bushing lubricated, but Chrysler must have specified the lubrication fitting be removed and capped off. Surrounding the upper bushing is a cavity filled with cotton felt that was saturated with oil when the distributor was new. Over time, this oil dissipates and the upper bushing starts to squeak and wear rapidly. My DIY rebuilt will have an oil cup with a spring-loaded cap so I can add a few drops of SAE 30 weight non-detergent oil a couple times a year. I'll provide the maker and part number of the oil cup as a post when I'm finished with the rebuild.

With regular fresh oil, the upper bushing should last much longer than the original. There is no reason anyone couldn't take a new factory-rebuilt 4.0L distributor and drill out the 5/16" plug and install an oil cup to keep the upper bearing lubricated. The blocked-off lubrication port is easy to spot; it's on the top of the distributor housing's narrow part and is 5/16" hole with what looks like a tiny upside-down Coke bottle cap pressed in for a plug.

I hope this was helpful.

 

My 2000 XJ has the same squeal, it is driving me crazy trying to track it down. It goes away when the engine is under a load but comes back as soon as you let off the gas. It is not there at all when the engine is cold, but shows up as soon as it warms up. I will look for these problems ASAP, but would like to know if any of you had any other solutions. So far I have replaced the idler pulley, belt, radiator, (found a leak), and the belt again (thought maybe the anti freeze had contaminated the belt causing the squeal. But the squeal is still there. Please help.

 

Did you check to see that the pulleys are aligned properly?

 

I did, they all look fine, ran a steel straight edge from pulley to pulley and didn't notice any variations.

 

If all components spin freely without the belt and harmonic balancer/crank pulley is in good condition, a squealing belt means that it is not tight enough. Tighten it in small increments until squealing stops and no more. You do not need a gauge to tell you when squealing/chirping stops.

 

Exactly...