Bad Coil?

[Matthan]

I have a stock 383 big block with a 4bbl on it and My charger seems to crank fine but after I drive it for about 15 min or so and cut it off it will not crank....after it sits for about an hour it cranks up....I am thinking my coil is bad....it looks old and gets very hot after I drive the car for about 15 min or so...any help?

[Pete in NH]

Hi,

That doesn't really sound like a bad coil. If it will not crank I would check things like the bulkhead connector pins, starter relay and the starter itself. When it won't crank try placing a  screw driver blade across the battery stud terminal to the starter solenoid terminal on the starter relay.If it cranks then the relay or wiring before it is the problem. Many times corroded or burnt pins on the bulkhead connector will act like this. Perhaps others will have a few more ideas.

[firefighter3931]

By crank, do you mean not turn over or not start ? 


Ron

[Matthan]

it will not start it is turning over...sounds like it just not getting fuel..i have a new carb, plugs, fuel pump...only happend if i drive it for about 15 min..the coil is monted on the intake.

[Dino]

You are in luck as I now am a total expert on coils!  No not really but I still may be able to help.   

To make sure the coil is good you can check the resistance between center and negative and once more between + and -.  You'll need to find the specs of the coil you have to compare.

Coils do get hot and I can only assume even more so when bolted to the manifold.  Mine's on the frame and still gets plenty hot.

[PlainfieldCharger]

My car was doing this. It was running ok as I just got it going after I drove it 10 miles or so the engine would die. The starter turned the engine over fine but no firing up. Hour later it would fire up. Die after 15-20 min. Put in my extra ballast and module...same thing. Had an Accel Super Stock coil that came with the car. Changed that out. Fixed many of my problems. Engine had some stubling and seemed to running rich. It is all gone now. 150 miles and no problems. I even had it out when it was 90 and no problems. It is a cheap fix...

[Dino]

Yeah the Accell's are pretty cheap, I have the same coil.  It's less than $70 new if I recall.

[firefighter3931]

it will not start it is turning over...sounds like it just not getting fuel..i have a new carb, plugs, fuel pump...only happend if i drive it for about 15 min..the coil is monted on the intake.

Next time it happens check for spark....if you have spark then the problem is fuel delivery.   

Vapor lock would be the most likely culprit based on the symptoms described 


Ron

[Dmichels]

I had a coil do exactly what you describe. IT would start and run fine, but would crap out after about 10 min. THe coil was really hot. Once it cooled down it ran again.
Dave

[Canadian1968]

I just went threw some coil problems of my own.  I was also running one of those accel super stock (chrome) coils. The thing only had... MAYBE 10 hours of run time on it. I swapped in Street Fire (MSD) coil. No problems since.  Check the resistance of yor ballast, the ones that come with the Mopar conversion kit is a .8 ohm which gives your 10V at your coil. You can purchase resistors that will give you 1.4 ohms from Napa and in turn your get a lower voltage at your coil.

I feel that could have been contributing factor that cooked my coil so fast.