Yes that is correct, I errored when I said disconnect the ECU and you should have voltage on only one pin. The dual relay needs a ground on its pin 85 to operate. That ground passes through the ECU to ECU pin 28. If the ECU is not plugged in the dual relay con not operate and power the the fuel injectors. Sorry my mistake.I think I read the ECU has to signal the dual relay for it to work?
You have done so much and the engine still does not run It's a true head scratcher.
I could be wrong but if the injectors are working and just the cold start valve is the problem, I think the engine should continue to run after it starts on starting fluid. Its my understanding the cold start valve only operates while the ignition switch is in the "start" position or when the thermal time switch is below 90 F. The thermal time switch will activate the CSV for close to 10 seconds. I don't think the cold start valve is preventing the engine from running once it starts on the starting fluid.
I like to remove the black plastic cover from the top of the air flow meter and inspect inside. The flap should move freely and return to the stop freely. The printed circuit board should be clean and the resistive arc should not be worn through. Its easy to observe the fuel pump switch contact operation.
I am pretty sure I have a spare working ECU. Ill ship it to you if you like. Email me you address my email is: flyme194@gmail.com
I assume you have removed the distributor cap and inspected inside.