Forgive me; we're just returning from dinner.
So, to answer your first question, at the PCM, where I had spliced in, I did NOT cut the brown/tan, at pin #16', as I instead terminated its other end at the fuel rail harness. So...effectively...the fuel rail harness does not know it exists.
BUT... this particular issue is now moot... Because I FOUND/discovered... That my splice was itself ineffective... Because while it -only an inch or so from the actual physical PIN #16-- was dead.... The paperclip jammed INTO THE PIN CAVITY, WAS LIVE!!!!
But...(there's always some complicating "but") I have found that PIN NUMBER 16 feeds through to fire injector number 5!!!! Which is SUPPOED TO BE FIRED BY PIN 15!!!! Which is brown/violet!!!
So I might have some kind of crossed wires! So I dismantled the plenum ONE MORE TIME....and SPECIFICALLY tested the light bulb trick, and it was setting off INJECTOR NUMBER 5!
And when I disconnected the #5 injector at its own plug...the firing clickety click stopped!
So.... Now I'm going to TAKE OUT THE FUEL RAIL HARNESS ONE (last?) time...to trace it out painstakingly, to MAKE SURE that pin #16 shoots its signal TO INJECTOR 4!!!!!!
Am I on the fit track here?
Oh, and by the way... Just in case I'm stupid:
Firewall side is 1,3,5 (cylinders, spark plugs, and injectors)
side is 2,4,6 RIGHT? Because the wiring schematic says that #4... According to the assigned colors...is indeed radiator side, and center. 2on the left and 6 on the right. (just checking my stupidity meter...just in case)