fuel pressure regulator

[pro_steve]

There's also a setting where you need 120 bar at the fuel pressure sensor to fire the injectors.
If you're not getting enough fuel pressure it can be the pump (quite likely), regulator (very likely, but you've changed that), or the fuel pressure sensor (I've not seen many of these go wrong).

Can you attach a volt meter to the output pin and ground pin of the fuel pressure sensor whilst cranking? Through a rough calculation you should see about 0.36 volts?

Or easier connect PP2000 and log the pressure whilst cranking. Where are you based, I'm in Bristol if you need any help.