Welllll I found the problem. It was really bothering me that the pump sounded different. I undid one of the fittings to see what comes out of the in-tank pump line. I wanted to check it for water in the fuel.
Found the problem... the external pump is completely dry and there is 0 output from the in-tank pump.


Good thing I filled the tank up all the way... -cries in gasoline fumes-

This is a b230f 1990 Regina/Rex - but I put an external pump on it after my friend had problems with the fuel system. Now that I've muddled my way through the external plumbing (which was a real adventure) and put a new pump in under the car, I need to convert the tank pump to the bosch version.

I also think the sending unit is misaligned or the pump is installed too low because the tank bung nut won't quite screw in all the way because the sender is sticking out ever so slightly.