Ignition coil gets hot
- Thread starter Pompis
- Start date
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68gtxman
I used to reMember
The job of the ballast is to reduce the voltage to the coil after the engine starts and warms up. If the ballast breaks down, it normally fails open, meaning that no power at all will be sent to the coil and the car won't start. I don't know if it can fail closed, thereby keeping the full 12 volts to the coil while the engine is running.
67Dart273
Well-Known Member
"My General Motors gets bad gas mileage."
We need some more details.
What are you running specifically for a coil, for an ignition system?
Have you checked charging voltage?
68gtxman
I used to reMember
D you have a voltage-ohm meter? If not, you'd better get one from Horror Freight fast! They are practically giving the away. Then check the resistance between both terminals on the ballast. If the reading is 0.0 then there is a sort in the ballast, so replace it.
TrailBeast
AKA Mopars4us on Youtube
An old canister coil can leak and then get hot for no other reason also.
BillGrissom
Well-Known Member
What temperature is "hot"? Normally, it will get warm, maybe so you can hold your hand on it for 10 sec. If so hot you can only touch it < 1 sec, that is "too hot". At that point, your spark will start missing at higher throttle. How I know, I hot-wired +12 V straight to coil+ to drive my Valiant home after it stopped from a problem in the ignition supply and it ran fine for 5 minutes until the coil got too hot, then started missing above 40 mph. Jumpered in the ballast and ran fine.
pishta
I know I'm right....
Also check your spark plug wire resistance. If they are shot, and measure off the chart, there is no where for the high voltage to go and the coil gets very warm. HF sells a digital VOM with a backlight for $4.88! Less than the one without a backlight....
It's a 318 from 73 with electronic ignition and the coil looks like a standard Bosch. I have voltage-ohm meter so i will check those thing you mention. The thing is the car runned fine when it suddenly stopped and i couldn't get it fired up again. Me and dad had noticed before that the coil get warm (Wrong of me write hot when you doesn't get burned on the coil). And my dad told me that the coil shouldn't get warm when running so i believed maybe that the coil failed and that's why it doesn't start. Like i said earlier the ballast is cracked and taped together so a new one is ordered. Forgot to check if it was any spark... Thank you all for the input in the thread.
67Dart273
Well-Known Member
As Bill said earlier, coils DO get "warm." We have to nail down the definition of "warm" and "hot."
As an example, I'm running a GM HEI module with NO ballast and with a stock coil. It does get "warmer" or "hotter" than I'd really like, but I've "watched" it and it doesn't seem to hurt. On a hot summer day but before the engine really gets fully cooking "under there" my coil runs warm/ hot enough that I would not want to hang onto it for more than about 10 seconds with the palm of my hand. Bear in mind that the engine will transfer a LOT of heat to the coil.
If you are exceeding this, you likely have a coil going bad. Also bear in mind that if you are running a Mopar ignition box, you DO want to run a ballast.
As an example, I'm running a GM HEI module with NO ballast and with a stock coil. It does get "warmer" or "hotter" than I'd really like, but I've "watched" it and it doesn't seem to hurt. On a hot summer day but before the engine really gets fully cooking "under there" my coil runs warm/ hot enough that I would not want to hang onto it for more than about 10 seconds with the palm of my hand. Bear in mind that the engine will transfer a LOT of heat to the coil.
If you are exceeding this, you likely have a coil going bad. Also bear in mind that if you are running a Mopar ignition box, you DO want to run a ballast.
63VALIANT*KISS
Well-Known Member
my car was driving fine then my car wouldnt start in front of my buddys house sat there starting and cranking but nothing i got a new super stock coil and started right up
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