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View Full Version : Can a faulty ignition coil cause a fusible link to blow?



ripper
18th February 2011, 11:21 PM
Today I fitted a Pertronix Ignitor ignition module in our Patrol to replace the points, and also one of their "Flame Thrower" coils.

As soon as I tried to start it I noticed it was cranking slower than usual. Thought it may have been trying to kick back, so retarded the spark a bit.
When I was retarding the spark I noticed something smelt a bit hot, but couldn't see anything, so figured it must just be the new coil warming up.
Tried to start it again, got it to fire once then it died. Look under the bonnet and there's smoke coming out from under the air cleaner. Freaked a bit till it cleared, then could see that it had blown a fusible link.
Now it wont crank over (obviously no power to the starter).

Could a faulty coil draw enough current to blow the link? Or even just the high performance factor cause too much draw?
Read on another forum that there have been a few epoxy "Flame Throwers" which were faulty from the factory.

Any other ideas as to what might've gone wrong?
Thanks.

ripper
19th February 2011, 02:05 PM
UPDATE
Found the problem, it wasn't the coil.
When I put the new coil in I took the ballast resistor out. The output wire from the ballast has no power in it when the ignition's on, but becomes live when the engine's cranking. I forgot about that and had it touching on the body.

There's still some issue with the coil though. With or without the ballast resistor, it doesn't discharge while the engine's cranking. Without the ballast (which it isn't supposed to need) it discharges just as I turn the ignition key off. It also starts and runs really well with a test light on the positive terminal. That made me think it wants some resistance but maybe not as much as the ballast gives.
If no one has any other ideas, I'll contact Retro Rockets next week and see if they've seen this happen before.

For now I've put the old coil back on and it's going well. Monday it goes on a gas analyzer to give it a tune up, I was hoping to have the ignition system all updated before then.