Okay, this is a little weird. In all the years I've been working on cars, I've never had to test a coil before (just lucky I guess). This morning my '73 Dart wouldn't start...no spark. I removed the negative wire from the coil (and old Acell Supercoil) and made a short jumper wire to replace it that I could tap to ground to trigger the coil. Then I pulled the coil wire from the center of the distributor and held it's metal connector about 1/8th" from a ground. I turned on the power and tapped the coil ground wire to ground a few times. My theory in this was that holding the negative wire to ground would charge up the primary, and then removing it would collapse the charge in the coil and I'd get a spark off the secondary cable held a bit off of a ground. That's the way they work, right?
I got nothing after trying this a few times. So then I hooked up a known good coil....with the same results! No spark at all. Nada! Frustrated, I went ahead and wired in the known good coil. I gave starting it one more shot for the heck of it...and it fired right up!! What!!? What was I missing in the spark test? I've been told before that such a test might require a condensor on the negative coil wire before a spark can be acheived, but this car has the early ECU ignition and there's never been a condensor on the car.
What have i missed? Thanks!
I got nothing after trying this a few times. So then I hooked up a known good coil....with the same results! No spark at all. Nada! Frustrated, I went ahead and wired in the known good coil. I gave starting it one more shot for the heck of it...and it fired right up!! What!!? What was I missing in the spark test? I've been told before that such a test might require a condensor on the negative coil wire before a spark can be acheived, but this car has the early ECU ignition and there's never been a condensor on the car.
What have i missed? Thanks!
