2005 4.3 MPI loss of fuel pressure

[NzTrailerBoats]

I had my engine out, fully replaced the block and heads etc and all the external parts had been sitting for about 4-6 months. Come to put everything back on I have found my fuel pressure is only sitting at 25PSI, therefore I can’t get the engine to start with its pre pistons and rings and internals etc.
Has 2 pumps, and runs raw water cooling

Rises to 30psi with pump running, drops to 25psi.
Block return line, pump running rises to 70psi, drops back down to 25psi
(Already order another fuel regulator that sits on the cooling system)
Clamp supply line just after the high pressure pump going to fuel rail, stays at 70psi
Have been told the pump doesn’t have an internal check valve, could there be one elsewhere? Or what am I missing?

Have been told there is another pressure regulator on my fuel rail for my model, but if that wasn’t working it should be staying at 70psi after clamping just after the high pressure fuel pump.

What am I missing here? Is there an external check valve I have missed?

P.s. it is very hard to see in the general area as it’s a tight fit in the engine bay

 

[alldodge]

Welcome
Could use your motor serial number to verify parts

Your will have the main Reg on the Cool Fuel module (item 13) and another Reg (actually a damper) on the Fuel Rail (item 18)

The Reg on the cool fuel is the one which controls main pressure. Looks like the pump is working fine and it's just the Reg