3VZE Rebuilding Engine Wiring Harness

Title is pretty self explanatory but I am going to be attempting to rebuild the fuel injectors portion of the wiring harness for my 3VZE 4r. To make things clear it does not look like there are any redeeming qualities to the original harness, not only are the injector plugs crumbling (which prompted me to at least swap those out) but the sheathing on the wiring itself crumbles if you look at it wrong. It's not salvageable in any way.

I am, however, comfortable with wiring of my own, have done major motorcycle rewiring electronics work among other various wiring jobs in other applications. I am comfortable completing the job and plan on doing it one connector at a time so as I don't lose my place in the harness and have the tools available to make it a pretty clean deal. With all of the intermittent no start and poor idle issues this engine has thrown at me, it seems like a good place to start seeing how bad they are.

Looking for any and all advice on this task. Is it worth it? Is it better to redo more of the engine harness than just the injectors if I'm going this far now? Any solid remanufactured harnesses on the market? Do I shill out for the 70+ dollar set of connectors or will the sub 20 dollar Amazon specials work just fine? Are there any other things I should be worried about? There should be minimal stressors to the connectors themselves because I plan on doing this hopefully once and the right way; and plan on cleaning out injectors and re o-ringing them while I'm in there.

 

I have a 1991 Toyota Pickup with 6cyl 3VZE. I won't bore you with the "spark, fire, crank but no start" story as it is quite long and sends me into a Toyota PTSD episode. Anyway, after trying to track down the issue, I believe that it has come down to one of three issues - a injector that is stuck open OR the injector harness has a short to ground OR a short in the wiring from the injector harness plug to the ECM (or possibly and ECM issue).

I cannot find an injector wiring harness and was wanting to know how your DIY project worked out for you. As it seems that this item may no longer be available online (or at least that I can find), I am also considering building my own. I am not looking to take on the entire engine wiring assembly - just the injector wiring harness up to the point that it terminates with the ECM (and, or the the wire bus going to the EMC. I would like to ask you a couple of questions please.

Is there a wiring schematic for this assembly?
Do you know the part numbers for the connectors and pins that are the proper fit for the OEM matching components (i.e. injector connections, ECM / bus connections, terminations, etc.)?
Is there any special tips or tricks or pitfalls to avoid that you could pass on to me based on your experience in fabricating your harness?

Although not a skilled electrician, I am a decent DIYer and know my way around a solder iron and multi-meter. With the knowledge of the proper parts that I should be looking for, I am confident that I should be able to build a functional harness. Thank you for any assistance you may be able to provide to me.