No spark and i can only get 5V at the coil.

This is all you need to test the basics of the ignition. You can easily test the ballast separate. A battery, the ECU, distributor and a coil, and of course some test leads



Below, the basic diagram for a 4 pin ECU



Below, the wire for testing spark. I use my 12V test light. No, LOL the spark won't blow up the bulb



Below, the ground connection. ALL you need is one wire from batt NEG to the ECU case



Below, the two distributor connections. In the car these are polarity sensitive, but for testing does not matter



Below, the coil NEG connection



Below, battery PLUS connection, one wire to this terminal of ECU and jumpered over to + side of coil



Below, all hooked up and ready to test. Should produce sparks at least 3/8" and typically 1/2" long



Below, distributor "one wire" test. I have removed the other distributor wire for simplicity. Take the bare connector end or this clip lead (the yellow) and with everything hooked up, ground it repeatedly. Each grounding should result in a spark