Mech pump? if so, hook a 5/16 neoprene hose to the inlet nipple & run it into a nearby can of gas then prime the bowls & see what develops. this'll take the line rearward of the pump and the pickup/sock (all) out of the equation. Sometimes very worn pumps have a hard time pumping when being activated slowly with a slow cranking eng & you'll see the effect of that when a car has sit long enough to evap the bowls but with you priming the bowls that ain't an issue. the pump might be totally shot (whats the history on it) and do a good visual on the hard lines and the (2) short neoprene connector pieces (1) up front at pump inlet and (1) at the tank sending unit. I had a '83 Cordoba and the pump outlet nipple pointed to the horizontle line along the frame going rearward (no gas!) took a bit to figure that one out. it used a U shaped piece of hard line to route em right.