The screen disc in the injector holder was clogged almost completely.
But the "clogging material" was a bit different from past experience episodes (on other trucks of the same model).
Usually I find some gummy or oily consistency junk built up on the mesh.
This time was different in that there was a layer of "dry, granular particles" almost like sand in appearance that at first glance hid the screen and circlip entirely from sight.
Because I knew there was no way of pulling the disc up and out of its bore without some of that junk falling into the fuel passage below (and consequently migrating into the injectors) I removed the injector holder and turned it upside down over a clean metal dish on my work table.
Quite a lot (maybe half a tea spoon) of stuff fell out. The grains were easily crumbled when prodded with a finger. I figure the stuff was flaking off of surfaces in the regulator/vaporizer and delivery hose and transporting to the screen. While I had the holder off, I removed the injectors and pressure sensor and cleaned out the stripped holder with spray carb cleaner.
This truck came to us from another terminal back in the spring and so I don't know about how much use it got at its former domicile, but here at this location it is pretty much a "stand by" truck because our operators don't care much for Komatsus.
Out of a fleet of nearly 100 trucks we only have 6 Komatsu trucks, the rest of the fleet are 7F & 8F Toyota.
I think that inactivity is allowing the typically gummy heavy ends of fuel to dry out and subsequently shed off the insides of the regulator/vaporizer.
I removed the Nikki regulator and disassembled it.
The inside surfaces had a lot of dried material coating that is usually very much like tar.
I went ahead and dropped the parts into the soak for cleaning and installed a previously rebuilt regulator on the truck.
All is well now, but I still don't understand the ETCA voltage discrepancies (from the manual) that I see.