make sure you dont have both pumps running at idle , if you connected the hobbs to the led lead and left the pump connector with the jumper it will run both pumps, the fact that you say its 45 and then you can get 100psi swapping the connectors makes it a return line issue
if the filters for the pump are positioned under the return tube that the pumps mount to you could have blocked the return inside the tank. also make sure that you didnt connect the return line to the vent tube