Do you have a pressure gage installed? Its possible to have volume but low pressure.
Does the fuel rail have a return line? If not do you have an air lock in the rail?
Worst case - pull the rail and injectors as an assembly then set up 6 containers and set the injectors into the containers. With the coil packs diconnected - crank the engine with the pump enabled. After 20 rev's of the crank or so check the fuel level in containers. The levels should be very close. Watch the spray pattern for low pressure (dribbiling fuel).
