Ignition Coil

Does the 4.0's coil have any major differences over any other vehicle's coil?
Mine seems to be overheating and whatnot and I'm brainstorming possible solutions.

What year Jeep?

Coil is overheating?

old worn plugs can make a coil work at 50-60 thousand volts, wires, cap and rotor too! the normal working voltage for a coil is around 11,000-15,000 volts. so a worn ignition system can cause the expoxy to crack on any coil.
here is a pick off a toyota car with a cracked epoxy coil. it cracked (overheated) from putting out to much voltage! mike

Pic of cracked coil:

x99j said:

old worn plugs can make a coil work at 50-60 thousand volts, wires, cap and rotor too! the normal working voltage for a coil is around 11,000-15,000 volts. so a worn ignition system can cause the expoxy to crack on any coil.
here is a pick off a toyota car with a cracked epoxy coil. it cracked (overheated) from putting out to much voltage! mike

Pic of cracked coil:

Click to expand...

x2

take a good look at every thing and if it even looks remotely worn out damaged or dirty you may want to replace it. (by dirty I meen crusty deposits on electrodes or contacts.) also check the plug wires for continuity and excessive ohms I had one wire I guess break in side the silicone cover and it was confusing the hell out of me as it would show continuity but when Id ohm it out i got varying numbers depending on where I was holding the wire. I replaced the wire set and the coil acted just fine. Also coils do go bad and or get damaged so if nothing else seems out of spec get a known good coil (note I did not say new) put it in and see what happens. If it fixes it buy a new one.

x99j said:

old worn plugs can make a coil work at 50-60 thousand volts, wires, cap and rotor too! the normal working voltage for a coil is around 11,000-15,000 volts. so a worn ignition system can cause the expoxy to crack on any coil.
here is a pick off a toyota car with a cracked epoxy coil. it cracked (overheated) from putting out to much voltage! mike

Pic of cracked coil:

Click to expand...

x2

take a good look at every thing and if it even looks remotely worn out damaged or dirty you may want to replace it. (by dirty I meen crusty deposits on electrodes or contacts.) also check the plug wires for continuity and excessive ohms I had one wire I guess break in side the silicone cover and it was confusing the hell out of me as it would show continuity but when Id ohm it out i got varying numbers depending on where I was holding the wire. I replaced the wire set and the coil acted just fine. Also coils do go bad and or get damaged so if nothing else seems out of spec get a known good coil (note I did not say new) put it in and see what happens. If it fixes it buy a new one.

Euclid said:

Does the 4.0's coil have any major differences over any other vehicle's coil?
Mine seems to be overheating and whatnot and I'm brainstorming possible solutions.

Click to expand...

Hallo. I renewed my ignitioncoil too. What a difference!
When the ignitionkey is on without starting the car, overheating is a possibility. Also bad contacts and cables with a high resistance.
On my 92' the ignitioncables were bad. I took measurements with a Ohm meter. The old ones were sometimes 10 times in Ohms value! in comparing the new ones. Greetings from holland:wave:

It is a 1996 XJ 4.0 auto.
When the engine bay gets hot sometimes it will just die and won't start back up until it's cooled off. No spark. Pooring water on the coil to cool it off usually fixes the problem which is what makes me think the coil is the culprit.

I will replace the plugs/wires first as I am unsure if/when the previous owner replaced them. Any reccomendations?

Thanks again