Coil Autopsy

Coil Autopsy

This coil was purchased just a couple months ago at Autozone in California while troubleshooting a problem that ended up being the fuel filter. On Father`s Day this year I started feeling an occasional misfire that increased in frequency to the point where I could barely drive the bus. Swapping in the old original Bosch coil got things back where they should be.

Here`s the shiny relatively new coil:

First I drilled two holes to drain the oil. I set it so when I drilled the vent hole the drain hole would be right over the opening in my drill press platform. Wasn`t much oil in there.

The coil after going around the top with a reinforced cutoff wheel on my Dremel:

Well, I was disappointed to see just how this thing was constructed. The windings are embedded in paper and only use less than half the available space. There`s an obvious scorch mark in the paper nowhere near the windings. Odd. The windings are two separate sets as expected around a steel sheet metal box.

That scorch mark may or may not be why the coil failed. I haven`t unwound the thing, and probably won`t. The paper just disintegrates when I tug on it. I would, however, be curious to compare this to a known good quality coil. But I don`t have one to cut up, so this will have to do for now.

I would have returned this turkey to Autozone if I could find the friggin receipt. Grr....

(Please ignore the messy garage. The apartements have been undergoing painting for 2 months now and all my patio stuff is in the one car garage.)