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Bad Coil?

Red63440

Red63440

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1964 Plymouth Fury - 361 with electronic ignition, stock coil, new plugs and wires.
Starts fine, plenty of power, idles fine no back firing, drives fine....turn if off and you can't get it to restart. Getting fuel and turning over fast...
Finished installing a new carb, intake and fuel lines today....car started fine, idled smooth and ran fine. Turned it off and it won't restart, same problem as before. Installed all new vacuum lines, checked all fittings, everything is tight


Could it be a bad coil?
 
Could be, was the coil hot to the touch?
 
Very much so.....actually hotter than the engine
 
Pull coil wire and check for spark right after shut down. Pull plug wire for spark if coil has spark.

Check magnetic pickup in the distributor for continuity immediately after shutting down. They will fail when hot and work again when they cool off.

Check bulkhead connections for corrosion. Check ignition switch.
 
Red63440 said:
1964 Plymouth Fury - 361 with electronic ignition, stock coil, new plugs and wires.
Starts fine, plenty of power, idles fine no back firing, drives fine....turn if off and you can't get it to restart. Getting fuel and turning over fast...
Finished installing a new carb, intake and fuel lines today....car started fine, idled smooth and ran fine. Turned it off and it won't restart, same problem as before. Installed all new vacuum lines, checked all fittings, everything is tight


Could it be a bad coil?
Click to expand...
When does it restart?
 
It has to set about 30 minuets before it will start again. I installed a new factory fuel line from the fuel pump from the carburetor including a new see through filter, fuel line is away from the block so I don't feel its a vapor lock issue because I poured some fuel into the carburetor and it still wouldn't start.
 
Was this always an issue or only after the change to electronic ignition? If it came after the change make sure your getting 10-12 volts in the start position at the ballast resistor. You may need another person to crank it when you check for volts in the start position. You can do like I do with leads on VOM long enough and with alligator clips and bring meter to windshield and see what you have.
 
It was like this when I purchased the car and it had already been converted to electronic.
 
Do you have a spare coil or borrow a known good one to verify?
 
Wish I did but no I don't, that would have been to easy.
 
Could be the coil for sure. Make sure it is for electronic ignition also. The pickup can also fail as stated but a really hot coil is not good
 
Might not be a bad idea to buy another coil to test it.
If that's not the problem, keep it as a spare. If it is, then buy another. Never hurts to carry a spare.
 
Let me ask this, what happens if you use a regular coil instead of one made for electronic ignition, the answer may help to explain the problem.
 
Ok, went out this morning and bought a new coil for electronic ignition and installed it. Car seemed to start quicker and since it was the first time to drive it since the update I was anxious to get it out. Took it out and drove for about an hour, thing runs very strong for a 361. Got home, pulled in the driveway and turned it off, let it sit for a few moments and tried to start it......wouldn't start, crank yes, start no. Pulled the distributor cap off to take a look, guess I was hoping something would jump out at me. Looked up on the firewall and saw the ballast resistor and remembered I had bought a spare. I thought what the hell so I changed it out......car started right up...go figure!
 
Red63440 said:
Let me ask this, what happens if you use a regular coil instead of one made for electronic ignition, the answer may help to explain the problem.
Click to expand...

There are several possibilities...
1. If using a "regular" coil....If the coils primary resistance is lower than a coil specific to electronic ignition, the coil will draw excessive current, causing it to over heat. The ECU will likely fail overtime, because of the excessive current it is switching.
2. Mopar's replacement coils are marked for electronic ignition as well as points ignition...check the coil's markings OR measure the primary resistance of the coil being considered to that of a Mopar coil.
3. Both coils noted previously require the use of a ballast resistor that is compatible, to LIMIT the current in the coil's primary windings and switching transistor must handle.
4. USUALLY, switching coils, in search of better ignition or higher secondary voltage will result in a component failure over time.

For your immediate issue, simply substitute a known "good" coil, the one that you now have. And insure that you are using the correct ballast resistor for the application. Just my opinion of course.
BOB RENTON
 
This is about to drive me nuts...
PLEASE, can we get a "final answer" here?
For those of us with the Mopar electronic ignition conversion kit specifically,
exactly what coil and ballast should we be using?
As in, what did Ma herself specifically design the things to work with?
 
Any coil designed for an Inductive ignition system

Typically around 1.4-1.5 OHM Primary resistance
Typically around 8,000-10,000 OHM Secondary resistance

Ballast Resistor no lower then .5 OHM Resistance to 1.2 OHM

You want at least 7-10 Volts at the positive side of coil with engine running

Don’t use a CDI ignition coil


Remember we are in the year 2020 where China and Mexico are making are coils and ECUs

Not the 70s and 80s of Direct Connection and performance USA made where we had quality components that where designed around a certain ignition system
 
Red63440 said:
Ok, went out this morning and bought a new coil for electronic ignition and installed it. Car seemed to start quicker and since it was the first time to drive it since the update I was anxious to get it out. Took it out and drove for about an hour, thing runs very strong for a 361. Got home, pulled in the driveway and turned it off, let it sit for a few moments and tried to start it......wouldn't start, crank yes, start no. Pulled the distributor cap off to take a look, guess I was hoping something would jump out at me. Looked up on the firewall and saw the ballast resistor and remembered I had bought a spare. I thought what the hell so I changed it out......car started right up...go figure!
Click to expand...

How was the wiring harness ends that connect to the Ballast Resistor itself

Just you removing the wiring from the old to new resistor could have been enough to cause a connection for voltage to the positive side of coil
 
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