Engine will not start

Blue wire...........Is the wiring hooked up to both ends of the voltage regulator? In your photo, this is the small box between the master cylinder and the fender.

Here is the basic circuit for the ignition:

The wire labeled "existing wire" at top right goes off to switched "ignition run" coming from the key. This should be "hot" in other words with the key in the "run" position.

NOTICE here that you are "looking down" at the rear of the ECU connector just as you are "looking down" at your ECU in the photo. So if you remove the plug from the ECU (remove the screw) turn it upside down, you should be able to take your meter and with the key in "run" determine if the box is getting power from the key