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

YoungDart75 said
Well after this im going to be trickle charging the battery tonight and then having it load tested tomorrow first thing.
All the below voltages were taken while turning the motor over attempting to start it. This was immediately after the battery read 12.1V with key off and not under load.
Battery power = 8.4V
Power to coil + = 7.2V
Power from negative coil to ground = 1.8V
Power to ignition(red wire) = 8.4V
Power from ignition(brown wire) = 7.7v
Ecu case voltage(case to ground)= 1.5 millivolts

Good deal; that is one reason you were asked to check the voltages all through the circuit; it was not clear if the battery was holding up a good charge. The good news is that it looks like the brown wire is carrying a 'decent' level of voltage through it; there is 1.2v difference from battery to coil + in START; the voltage drop ought to be less than that but is not a complete disaster. If the battery holds up to a charge and load test, THEN see if it will crank and fire and run the other checks.

It still looks that you have some voltage drops between the ignition switch and the ignition system. Probably in the connections but possibly the wires are going bad (internal corrosion) or there is another hidden splice in there. Feel along the wires and see if you find any soft spots or unusually hard spots or other irregularities.

One good indication from your complete voltage tests is that it looks like full battery voltage is reaching the ignitions switch. That says that your wiring and connections via the start relay and through the fusible link and on to the ignitions looks to be good. That is a plus and another reason to take complete readings.