Ignition Failure, Fried CDI, what's causing it Options

[DonTraver]

Went out to start the 6 today. She's got a stock Bosch Ignition system, Bosch distributor and CDI box.

Anyway, she cranked but wouldn't start. So I hooked up a timing light to check for spark, no spark. Installed a spare Petronic's CD box to replace the original Bosch CD box. Started right up.

Let her run for about 10 minutes while checking some other things, lights, turn signals, etc. Reached in to goose the throttle, she died and wouldn't restart.

Hooked up the timing light again, no spark. Replaced the CD box with my last spare and she fired right up.

Now I'm wondering if this is just coincidence or is there something causing the CD boxes to fail.

It's got me baffled, I know that's easy to do.

Anyone got any ideas, I really hate to fry these things, they're not cheap.

Any help appreciated.

Thanks, Don

[brp914]

Don't toss the bosch CD. I had mine rblt for ~$100. But that was probably 10 yrs ago. I may still have the contact info, but not with me since I'm at work. The rblt doesn't whine, which is too bad since it sounded kinda cool before and let you know it was working.

As for cause, unfortunately I'm easily baffled too, so besides coincidence, these are WAG's:

did you drive it in the rain? maybe water in the wiring.

check wiring from CD to coil for abrasions causing short to ground

clean contacts on CD and coil

low coil primary resistance