Did you verify that the PB sleeve or screw is installed? Did you check with air.
If you have all hoses connected correctly, and the path is from pump to FEL PB out, then to IN port of new valve, then to 3pt, you should have fluid at pressure on the QD when you activate the lever.
You are checking the pressure at the work ports, correct.
Did you hear the relief?
If you have no fluid to the new valve, that means that the FEL PB is not installed, and therefore the fluid from the FEL is flowing through the return port to tank.
Do you have 3pt?