The correct way to test the regulator is to block the return line.......then cycle the key on to off several times(10 seconds in between), to get max pressure......if pressure stays low, you need a pump(change fuel filter first before doing this test).....
If you have rubber fuel hoses, the return can be clamped with a rag and vice grips....
If you have plastic lines, then you need a special tool....a shut off valve that is designed to be inserted into the return line....