Help with coil or ignition.

[SnoPro440]

The other day when I drove my Charger to work, I noticed it was running a little rough but nothing too terrible.  When I left work, I had a hard time starting it and once it did start, it ran pretty rough.  I limped it home, popped the hood and let it cool off.  Went back out a few hours later to check the plug wires just to make sure that none of them were loose.  Well, I pulled on the wire that goes from the coil to distributor and the end that plugs into the distributor, fell off.  The wire itself was charred black.  The spot on the distributor that it plugs into has a white residue in it.  What would cause that to happen?  I do not know anything about coils, ignition or distributors.  Is it possible that this Mallory coil and dist are just on their way out?  I don't know how old this stuff is because it was on the car when I bought it.  The only two things that have been changed since the body and paint were done is the 2" spacer under the carb was removed and I added the aluminum radiator.  Otherwise, the motor itself is the same as when I bought it 4 1/2 years ago. Here are some pics of the wire and under hood shots.

[maxwellwedge]

Possibly loose or cracked coil wire that caused arcing which eventually burned it through. Have you tried a new coil wire to see if it runs better?

[SnoPro440]

I will give that a try once I get another wire.  Do I need to worry about a possible fire?  Seeing that charred wire kind of freaked me out.  The pic I took doesn't show the part that I cut off.  I was trying to see how far back it burnt.  It was about a half inch.

[alcusswhen]

4 1/2 years is a long time to run a coil wire with a 45,000 volt coil. The coil wire with these systems gets really hot at the cap <the point of the highest resistance.> With time engine vibration shakes the wire back and forth like breaking a coat hanger, the longer this goes the hotter the wire gets because the wire core starts to break down rom that the wire case melts to the point that the clip can't hold it in. There's nothing wrong with your set up its just way past time for a tune up: Cap, Rotor, Wires and spark plugs. You need to pull and check the cap, rotor and all wires at least every six months. Some things never change with these old cars and that is one of them.

[maxwellwedge]

Try a new wire with the coil and distributor cap cleaned of any remaining crud. Make sure the connection is good and the wire fully seated at both ends. If it runs better you should be ok. Fire it up at night and have a good look at all your wires (the whole wire - both ends) and electrical connections around your coil - you should be able to see any sparks, arcing etc. Good Luck!

[maxwellwedge]

4 1/2 years is a long time to run a coil wire with a 45,000 volt coil. The coil wire with these systems gets really hot at the cap <the point of the highest resistance.> With time engine vibration shakes the wire back and forth like breaking a coat hanger, the longer this goes the hotter the wire gets because the wire core starts to break down rom that the wire case melts to the point that the clip can't hold it in. There's nothing wrong with your set up its just way past time for a tune up: Cap, Rotor, Wires and spark plugs. You need to pull and check the cap, rotor and all wires at least every six months. Some things never change with these old cars and that is one of them.

I agree - give 'er a good tune up after checking the coil and other wires out.

[SnoPro440]

Thanks for the info guys.     I'll let you know how it turns out.

[Purple440]

Yes, check your wires with a tester for resistance, and check the cap for corrosion.  I check mine every spring, and have had to replace two caps so far on my Mallory Unilite distro like you have....seems that driving in the rain a few times may have caused it.  Also had to replace my wires.  About 6k on the motor.

[General_01]

I don't know if this has anything to do with your problem, but I notice that it looks like your cap is not vented. I think Mopar vented the distributor caps to help prevent arcing across the gas created in the cap. Not sure, but I think that is why they did it.

[firefighter3931]

Yes, check your wires with a tester for resistance, and check the cap for corrosion.  I check mine every spring, and have had to replace two caps so far on my Mallory Unilite distro like you have....seems that driving in the rain a few times may have caused it.  Also had to replace my wires.  About 6k on the motor.

Good advice....look at the contacts inside the cap for signs of corrosion and replace as necessary. Doug makes a good point about venting....you can drill 2 small holes on the side of the cap to help the gases escape. Underneath the hold down clips is a good spot to drill.

Not a fan of accel wires....they generally don't last long and have a lot of resistance.  Get an ohm meter and test them just to see what you've got. If there is more than 100ohms resistance per foot then it;'s time to trash them. The plugs probably need to be changed as well. If you're running a stock cylinder head go with the NGK XR5's 

If the ignition wires are cooked (most likely) lemme know and i can fix you up with a set of Firecore 50"s....you won't find a better ignition wire...period ! 



Ron

[b5blue]

I testify to Ron's Firecore wires!         

[alcusswhen]

Thanks for the info guys.     I'll let you know how it turns out.

The first time this happened to me was August 69 at the Abbiville Dragway in Abbiville AL. A friend gave me an Accel super coil, but I knew nothing about the 1.82 resistor for points. I put the thing on Saturday mourning at FT Benning GA and drove down to Abbiville the car was rough buy the time I got there then it wouldn't start after it cooled off.
I had melted not just the wire but the cap terminal had a hole in it, the tip melted off the rotor and my points fried. It was a good thing I'd made friends with other mopar guys that lived close. Two of them went home and got parts. One had the resistor. When they got back two others fixed my car for me and told me about keeping an eye on the coil wire. It felt strange to me because those guys knew I was a multi tour Vietnam vet during a time when the country was still spitting and pissing on us. Morel: keep an eye on your car and mopar people are the best. 

[SnoPro440]

Ok, changed out the plugs, wires, cap, rotor and coil wire.  Now it won't start and I'm not getting spark.  I was told that it's probably the ballast resistor but unknown to me, my ballast resistor was not re-installed when my Charger was in for paint and body.  There was a jumper wire connecting the wires together where the ballast resistor should have been. I think the coil might be fried but how can I be sure?  I took the coil wire off of the distributor and had my buddy hold it to ground while I cranked it.  Nothing, no spark and it didn't even shock him.  Any ideas?

**I was looking at old pics I took and the ballast resistor was installed.  I also found a few after the motor was installed and it was there then.  I'm not sure when it was removed.  Without it in place, can that screw up the coil?**

[b5blue]

May have fried the ECU.

[TylerCharger69]

Maybe a possibility of a hair-line crack at the distributor cap causing those "charred" results?

[firefighter3931]

Troy,

I don't see an ignition box in any of your pics....what is on the car now ? Mopar ECU or some aftermarket box ?

You can do a resistance test on the coil with an ohm meter to determine if it is shorted out...



Ron

[alcusswhen]

Ok, changed out the plugs, wires, cap, rotor and coil wire.  Now it won't start and I'm not getting spark.  I was told that it's probably the ballast resistor but unknown to me, my ballast resistor was not re-installed when my Charger was in for paint and body.  There was a jumper wire connecting the wires together where the ballast resistor should have been. I think the coil might be fried but how can I be sure?  I took the coil wire off of the distributor and had my buddy hold it to ground while I cranked it.  Nothing, no spark and it didn't even shock him.  Any ideas?

**I was looking at old pics I took and the ballast resistor was installed.  I also found a few after the motor was installed and it was there then.  I'm not sure when it was removed.  Without it in place, can that screw up the coil?**

The una-lite is a stand alone it don't need a box. You need your ballest resistor thats what caused this to happen so fast. The resistor has two wires together that plug to ether side and a single wire that plugs to the other side. With a test light key in run position single wire unplugged should be hot double wire cold. In key start position unplugged the double wire should be hot. In start you bypass the resistor and send 12 volts to the coil for cranking. When you release the key the start wire goes cold and power goes in from the single wire to the resistor. This cuts the power to the coil to 6 volts to prevent frying the points, coil and cap with a una-lite it prevents frying the pickup. Old school coil test run a hot wire from + battery to + coil put a piece of wire on the - side of the coil, hold the coil wire about a 1/4" from metal then touch the - wire to ground and remove it fast if the coils good it will spark the wire. If you have power and a good coil the pick up fried. The mopar electronic ignition  conversion kit is still the best street set up money can buy.

[flyinlow]

Buy 2 coil wires. One for a spare. and a cap , rotor and a replacement for your longest plug wire. Put in trunk.

Having looked a hundreds of v8's on the old Sun machine with the an oscilascope, normal warm engine firing voltage at idle or light load was around 5000-10000 volts. The voltage would jump up to around  20000 under sudden hard acceleration. This was with resistor wires and plugs. The only time you saw the max voltage the ignition system could make was when a plug wire failed or fell off. (25000-30000v.)

[SnoPro440]

A little update on this.  I changed over to MSD for the distributor, ignition and coil.  The wires I got through Ron all had to get new ends put on so that sucked cutting brand new wires.  All was fine and dandy until the fuel pump decided to pop while we were tuning the carb.  Now that has been replaced too.  Next on the list is the carb and the intake.

[firefighter3931]

Keep at it Troy ! 

The MSD box and distributor are top shelf ! 



Ron