Causes of Ignition Coil failure??

[2005 Wrangler Rubicon]

I recently posted a problem I was having in diagnosing multiple cylinder misfires (see http://www.jeepz.com/forum/cj-yj-tj-jk/33087-tj-misfiring-cylinders-2-6-cant-identify-problem.html ), which, as it turns out was the result of a failed Ignition Coil.

Anyway, I have two quick questions on ignition coils.

- First, what would cause the coil to fail/break?

- Second, is there a way to manually test the 1-piece ignition coil? I ask because the technician told me that there is no way to do so, and that the coil testing is reliant on the diagnostic computer testing, which in this case, did not note a problem with the coil. He also says that this is the first 1-piece ignition coil that he has had to replace in 30 years of business.


Thanks in advance

 

[Bounty__Hunter]

They fail more often than what your mechanic has seen. I know of no testing procedure.

 

[Jester32]

Ya I've put three in mine in the past year. But that was 160,000 kms worth lol.

 

[Ggg]

BH can't you do an Ohm test like on old style coils?

 

[Bounty__Hunter]

Don't know what the procedure would be, and electrical is not my strong point at all LOL.

 

[lambo]

Just buy a new accel coil. You will get more power and better mpg,s.

 

[jfrabat]

I agree that they burn more often than not... I also have gone through 3 of them in the past few years... Including an Accel one and a Screaming Demon one. I just carry a spare one in the Jeep just in case now.

 

[Gr8tdragon]

Coils are a bunch of wire wound around a bunch of plates. The wires have a thin insulation on them as well as the plates have thin insulation separating them. Your trigger/input voltage (12- 14V) goes in on the wires. The output voltage is generated in the plates and goes out on your ignition wire to the distributor, usally 50,000 volts, low milli amps. You really can't test the coil cold as the insulation won't be failing then unless you have catastrophic failure. Then you could cut the coil open and actually see the burnt wound wire or the plates welded together. if your input voltage goes higher or lower then what the coil is rated for then you run the chance of burning out the coil, slow or fast depending on which way you change the voltage and how much you change the voltage by. If you can get a MSD coil, which I am going to buy for mine as I have used them before, the coil has a life time warranty. Sorry for the long winded electrical version.