If you are testing the pressure at the fuel distributor inlet, (rhs of unit), and its low, do a direct pump pressure test at that same delivery line, except dont use a T fitting, just connect deliv line straight to gauge. You need around 85 to 100 psi or more. If you still have 30 psi, there are a few things that could cause that. 1. fuel accumulater isnt holding pressure (you can plug its return line to see if pressure comes back up) 2. pickup screen in tank is dirty. 3. fuel filter clogged. 4. bad pumps 5. insuffcient voltage to pumps (bad relay contact) this would be rare, its either there or not. Do a fuel pump voltage test. 13.5vdc+ First get your straight pump pressure fixed, then worry about the FPR. Your goal is to have 80psi with the T fitting between the deliv line and fuel distributor.
Dave...