for fuel injection, it is above 30 psi and probably closer to 50 psi.
been a long time since I looked.
this from a generic website:
Engines with fuel injection will normally use electric fuel pumps to supply the higher pressure demanded by the system. With port injection, the required pressure ranges from 45 psi to 66 psi.
On throttle body injection (TBI) systems, the pressure is normally between 9 psi to 18 psi.