If I pull all fuses except the tank pump and main pump the voltage stays about 12+.
If I unplug the main pump the voltage jumps up to 13-14 for a few seconds before the car dies from lack of fuel.
The main pump is drawing about 4 amps, the tank pump is drawing about 2 amps, both of which are a little less than spec from what I read from others on the board.

It's hard to comment on this without knowing what model & year car we're talking about. Those pump amps sound low, yet from what you say they (or the main?) are dragging the alternator down. I've never had that kind of problem.

Maybe a new post, focussing on the pump readings, rather than calling it a "Charging Problem" would get some better answers
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.