Just put 12v directly to the lift pump, if it does nothing its broken.
I don't fully understand what your saying. Something about to intank pumps..
But just replace the lifter in the tank.
VL intank lift pump part number is Goss GE015
I reckon your surge tank and main pump are way to far away and would be stressing the intank unit.
I would be putting it at the back of the car. The is room at the rear under the car for a 1lt or smaller surge tank and pump.