check the flow of the walbro pump and check what it flows at 12v
how to install the map sensors is in the apexi documentation, check the PFC FAQ in my signature
if you want 1.3bar, then run 1.3bar actuators or as close to the target as possible
use your controller as a bleeder and make sure you are only trying to bleed a small amount, ie dont run a 7psi actuator and try to bleed 7psi