the reluctor tooth induces a slight AC voltage in the pickup coil & that "triggers" the ECU to unground the black/yellow wire from the coil neg pri terminal. the coil works opposite of other devices, it is being fed voltage & it sparks when the current is stopped & the magnetic field in that primary circuit collapses & induces a current in the secondary circuit (the large center post/wire). when you do the coil test you dont keep the coil neg primary terminal grounded like it sounded like you were saying (if I interpreted it right) but you tap tap the alligator clip to ground & it sparks when you lift it up off the intake (ungrounding it). OK, if dragging the pickup nub makes it spark in run and in crank with the ECU plugged in/everything else hooked up normal then all that is left is from the zigzag connector back to/including the pickup (electrically) & the gap (mechanically). You have provided excellent details but I feel I am inadvertently missing something. lets try this: repeat the zigzag dragging test BUT have a helper cranking the ign & see if the coil wire sparks.