No spark and i can only get 5V at the coil.
I did your test cor the coil and it passed. Then i pulled the wires and checked spark at 4/5/6 and got no spark to either of those 3. Swapped to a known good cap and rotor and still no spark at the plugs. Right now im thinking the distributor may be the issue. Not buying parts just yet. Going to double check timing again too.
OK that shows that the coil and power feed to the coil is essentially OK. The 1.3 ohm resistance reading of the coil primary is a good number.
What you have done by grounding the coil - (while disconnected from the ECU and distributor) and getting consistent spark out of the coil spark wire is to isolate the problem to those 2 units. The 'no spark at 4/5/6' verifies this. So you now need to concentrate on the ECU and distributor pickup.
1. Does the ECU have a good ground? Remove it and scrape it and the chassis under it clean and put in new bolts, preferrably with star washers.
2. Clean out the connector contacts to the ECU module and to the distributor pickup. Look inside the female pins to make sure they have not been spread open; if so, squeeze them to tighten them up.
3. I think you made the FSM resistance test of the pickup coil earlier; is this correct?
4. There really is not an easy way to test the ECU by itself. At this point, I would check voltage and continuity of wires to the ECU connector pins if you have not already done so.
5. BTW, you can eliminate the cap and plug wires as the issue by simply connecting it all up and cranking but take the spark wire out of the coil and set it 1/4" from metal. If you get no spark or erratic spark then the issue is not in the cap or rotor. I think you already did this but with a very weak battery, so I would recommend repeating it.
