1........It would be pretty damn handy to actually know what you are working on, or did I miss that?2.......Have you actually checked spark at the coil wire, how do you know it's spark and not fuel?3......Have you made any voltage checks, IE what exactly have you actually checkedA......Make absolutely certain the ECU is grounded MUST BEB.....Wiggle the ballast connectors, and the ECU and distributor connector. Work them in / out to "feel" for tightness and to scrub them clean.C.....Make some voltage checks. Turn the key to "run" and with the meter grounded to the engine, probe the ballast to find the highest reading. There should be two with high readings if a 4 pin ballast, one of the 2 if a 2 pin. Should be "same as battery" voltage.D....Check coil NEG terminal voltage. Should be quite low, perhaps 1/2 voltE....Check coil POS terminal. Should be substantially below battery, perhaps 5--10 voltsF...Remove the distributor connector and get the connector end going to the firewall. Try grounding first one, then the other pickup wire. One of them should give you one "snap" spark out of the coil wire.Dearly hope you did not clamp the welder ground onto the engine block.G....Remove the cap, inspect the inside of the distributor, for carbon, grease, water, spark damage. Inspect the rotor.Inspect the reluctor / pickup for strike damage, rust, debri. If you can get a .008" brass feeler and check the reluctor gap. "Feel" the shaft for side play and wear