99 Cherokee Sport Lmd
4.0 IL 6

I've gotten great help here before, so I'll try once again:

At about 75K miles, the distributor started sending out loud, high
pitch chirping sounds, like metal to metal rubbing.

I pulled the cap and noticed a fair amount of "crud" on the rotor and
on each electrod inside the cap.

I replaced the cap and rotor, and the chirping stopped for about day,
then started up again.

I pulled the new cap and noticed "arching" wear patterns on the
electrods, but nothing else (the new cap was on for about 500 miles).

I replaced the cap and rotor a 2nd time, but the the chirping started
up right away.

I can push on the cap to change the chirping/rubbing sound. Sometimes
there is no noise at all coming out (usually for less than a minute),
but sometimes the noise is quite LOUD. I'm very confused.

Why would this happen?

 

I found the inside of the cap on my new to me 96 Cherokee just like yours.
Does the shaft have sideways play? Mine had a lot and it must be a common
problem as the local AutoZone had one in stock. Easy to replace. Just one
important part Note exactly where the rotor is pointing before taking the
old one out. Then when you have a new one put it back in the exact place.
The distributor is held from turning so there's no timing there, just
getting the gear tooth back in position is the only trick. When you put it
in the rotor turns. You must calculate what direction and amount. You can do
this when removing the old one.

JoBo

"Football God" <footballgod214@hotmail.com> wrote in message
news:9dbaa85d.0408240642.923470d@posting.google.co m...
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I found the inside of the cap on my new to me 96 Cherokee just like yours.
Does the shaft have sideways play? Mine had a lot and it must be a common
problem as the local AutoZone had one in stock. Easy to replace. Just one
important part Note exactly where the rotor is pointing before taking the
old one out. Then when you have a new one put it back in the exact place.
The distributor is held from turning so there's no timing there, just
getting the gear tooth back in position is the only trick. When you put it
in the rotor turns. You must calculate what direction and amount. You can do
this when removing the old one.

JoBo

"Football God" <footballgod214@hotmail.com> wrote in message
news:9dbaa85d.0408240642.923470d@posting.google.co m...
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I found the inside of the cap on my new to me 96 Cherokee just like yours.
Does the shaft have sideways play? Mine had a lot and it must be a common
problem as the local AutoZone had one in stock. Easy to replace. Just one
important part Note exactly where the rotor is pointing before taking the
old one out. Then when you have a new one put it back in the exact place.
The distributor is held from turning so there's no timing there, just
getting the gear tooth back in position is the only trick. When you put it
in the rotor turns. You must calculate what direction and amount. You can do
this when removing the old one.

JoBo

"Football God" <footballgod214@hotmail.com> wrote in message
news:9dbaa85d.0408240642.923470d@posting.google.co m...
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I found the inside of the cap on my new to me 96 Cherokee just like yours.
Does the shaft have sideways play? Mine had a lot and it must be a common
problem as the local AutoZone had one in stock. Easy to replace. Just one
important part Note exactly where the rotor is pointing before taking the
old one out. Then when you have a new one put it back in the exact place.
The distributor is held from turning so there's no timing there, just
getting the gear tooth back in position is the only trick. When you put it
in the rotor turns. You must calculate what direction and amount. You can do
this when removing the old one.

JoBo

"Football God" <footballgod214@hotmail.com> wrote in message
news:9dbaa85d.0408240642.923470d@posting.google.co m...
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I do not know if this applies to the newer distributors, but on the ones
that have a mechanical timing advance inside, their is a place to oil it
that very few places seem to know about or do. There is a felt wick
under the rotor that needs engine oil added to it. This lubricates the
timing advance plates.

Maybe yours is dry?

The other thing to do is to grab the rotor and see if it has any side to
side slop. Maybe it just plain has a bad bushing in it, I think I have
heard of some newer ones being bad.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Football God wrote:
>
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I do not know if this applies to the newer distributors, but on the ones
that have a mechanical timing advance inside, their is a place to oil it
that very few places seem to know about or do. There is a felt wick
under the rotor that needs engine oil added to it. This lubricates the
timing advance plates.

Maybe yours is dry?

The other thing to do is to grab the rotor and see if it has any side to
side slop. Maybe it just plain has a bad bushing in it, I think I have
heard of some newer ones being bad.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Football God wrote:
>
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I do not know if this applies to the newer distributors, but on the ones
that have a mechanical timing advance inside, their is a place to oil it
that very few places seem to know about or do. There is a felt wick
under the rotor that needs engine oil added to it. This lubricates the
timing advance plates.

Maybe yours is dry?

The other thing to do is to grab the rotor and see if it has any side to
side slop. Maybe it just plain has a bad bushing in it, I think I have
heard of some newer ones being bad.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Football God wrote:
>
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

I do not know if this applies to the newer distributors, but on the ones
that have a mechanical timing advance inside, their is a place to oil it
that very few places seem to know about or do. There is a felt wick
under the rotor that needs engine oil added to it. This lubricates the
timing advance plates.

Maybe yours is dry?

The other thing to do is to grab the rotor and see if it has any side to
side slop. Maybe it just plain has a bad bushing in it, I think I have
heard of some newer ones being bad.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Football God wrote:
>
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.
>
> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.
>
> I replaced the cap and rotor, and the chirping stopped for about day,
> then started up again.
>
> I pulled the new cap and noticed "arching" wear patterns on the
> electrods, but nothing else (the new cap was on for about 500 miles).
>
> I replaced the cap and rotor a 2nd time, but the the chirping started
> up right away.
>
> I can push on the cap to change the chirping/rubbing sound. Sometimes
> there is no noise at all coming out (usually for less than a minute),
> but sometimes the noise is quite LOUD. I'm very confused.
>
> Why would this happen?

 

Football God did pass the time by typing:
> 99 Cherokee Sport Lmd
> 4.0 IL 6
>
> I've gotten great help here before, so I'll try once again:
>
> At about 75K miles, the distributor started sending out loud, high
> pitch chirping sounds, like metal to metal rubbing.

Oddly, it is.

> I pulled the cap and noticed a fair amount of "crud" on the rotor and
> on each electrod inside the cap.

That's oil vapor sneaking up and getting deposited in the cap.

The bushing in your distributor is shot. Time to replace the
distributor. http://members.***.net/wilsond/distributor/


--
-- DougW -- 93 ZJ 4.0 http://members.***.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!