D jet troubleshooting question, determining a probable wiring fault. Options

[Lowsquire]

Hi all you D-jet Gurus out there..

Heres the problem I have ,hope you can help.

73 1.7 stock car.
Hasnt run in many years I assume , I Bought it with everything removed and off the top of the motor. all the parts looked cleaned and (maybe?) checked or reconditioned. they may have just been wiped clean and put in bags? who knows?
Ive just got the whole thing back together and ready to start.lt Cranks over, fuel pressure, good spark..would almost catch , but not quite fire.
Through checking spark plugs and swapping injector plugs around, worked out I was only getting fuel out of one injector.
Confirmed this by pulling injectors, then operating throttle with ignition on, which allows the enrichment circuit to fire the injector, and you hear a series of clicks from injector.
Only one out of the four injector plugs seem to make the injector click.when i swapped the plug onto another injector that clicked fine and sprayed fuel,indicating injectors are fine.
SO next i checked and cleaned injector wire ground points and checked continuity to ground to the wires, and they all behaved the same, seemingly fine.
so where im at is working out if its possible that the computer is fritzed and only firing the one injector, or if its a fault in the loom.

I guess my question is.. does the signal to fire the injectors come out of the brain as four seperate wires, or two then split to the two banks, or a single terminal and split in the loom somewhere? a diagram of the connector pins would be a great start.. I guess stripping the loom out is next and checking for any breaks/poor connections.