It sounds to me like the bypass circuit is not working, Check a wiring diagram and see if it still shows the brown "IGN2" circuit.
Traditional mopar igntion electrics work like this:
Your IGN switch is actually SEVERAL separate switches in one container.
The (traditionally) yellow comes directly from the IGN switch, goes through the bulkhead to the start relay, and if the trans is in park/ neutral, or if you have a stick with a clutch safety switch, the pedal must be depressed, the yellow then will fire the relay in "start."
The (traditionally) brown IGN2 "bypass" circuit comes from a SEPARATE contact in the ignition switch, goes directly to the coil+ side of the ballast resistor. It is hot ONLY in "start" and it's job is to provide hot 12V to the coil when cranking.
The (traditionally) dark blue IGN1 "ignition run" is hot ONLY in run, NOT start, so if the bypass circuit is not working, this circuit will not provide IGN voltage to the ignition system until you release the key.
THE OPPOSITE problem happens when you have a bad coil ballast. In this case, the "bypass" circuit fires the engine during "start" but when you release the key, the broken resistor cuts voltage to the system.
ALL these older Mopars are developing problems in the harnesses and ESPECIALLY the bulkhead connector. I'd advise you pull it apart at the least and inspect it, as well as the ammeter for damage.
Read this article:
which came from here: