Fuel pump runs w/ AFM flap open

Okay, I've got a 1975 280z....hadn't been driven in several years. Ran like dog crap...replaced fuel pump, filters, wires,plugs....wouldn't turn over. Finally got it going by having friend hold AFM flap open....ran really well. Tried driving it around and eventually couldn't get it to restart. Still can hear the pump engaging when opening the AFM flap....just won't turn-over. Any thoughts on this?

Thanks much!

Saint