Here is an excerpt from a Mopar tech article, regarding a crank but no start condition: "If there's no spark, we go to step B. First, check the voltage at the "+" side of the coil, which may also be marked "bat" or "ECU." It should be at least 8 volts with the key in the "run" position, and within a 0.5 volts of the battery voltage during cranking. If it fails the "run" voltage test, swap the ballast. On cars with the old-style 5-pin ECU, try the ballast regardless of the voltage readings.
Still no good? Meatball surgery time. Run a clip lead from the "+' side of the coil to the "+" side of the battery. It will start now, but you'd better drive home fast, as the coil and ECU (or points) will be taking a beating. Safely home, you can check the bulkhead connector, ignition switch, etc."
If the coil "+" voltage is correct, but there's still no spark, either the ECU or points, depending on what you have, is probably the culprit. For points, you can disconnect the distributor wire from the coil, and measure the resistance from the wire to ground. It should pulsate from zero to infinity as the engine is cranked. No? Take off the cap, crank, and check that the points are actually opening. A quickie eyeball adjustment will usually get you going, but points have been known to "grenade," rivets actually popping out, arms breaking off, etc. That's why you packed a spare set, right?
If you have electronic ignition, and brought an ECU, you're in like Flint. Of course, occasionally the ignition coil itself, as well as the distributor's internal mag pickup coil and/or it's leads, will fail. Such is life!
