So I am now thinking it is the transfer pump.
I checked all ECM circuit breakers and I have good power all around.
When I look at the fuel delivery pressure reading on the VMS display while cranking, it's reading zero.
I see fuel come out at the secondary when I crank, but it's possible that it's just not enough pressure for the ECM to run the injectors.
If I had a way to put 20psi or so of fuel to the inlet side of the secondary I could confirm this. My last test involved filling the bowl on the Davco and leaving the upper cap loose while I cranked. There's enough fuel in that bowl to get the engine running and yet it is not firing. I see the fuel level in the bowl lowering, but very slowly; the bowl holds maybe a quart, and in perhaps 20 seconds of cranking about half of that has disappeared, probably right back to the tank via the return.
BTW, I have no way to put air pressure to the tank -- too many openings. But, really, this problem can not be between the tank and the Davco -- there's already enough fuel sitting in that Davco to run the engine. If there was an obstruction or an air leak between the Davco and the tank, it should run fine until the Davco empties, and then and only then should it quit. That's not what's happening here.
Anyone have a line on a rebuilt fuel pump for an 8V92?