LS1 not starting....less fuel pressure ?

[ACII]

Hy all

today it was time to get the engine firing up the first time after the swap.

Unfortunately the engine is not running...

The fuel pump is running ....also i do have a spark

But i am not sure how much fuel pressure the injectors need for proper working ??

At the moment i dont have installed a fuel regulator....so the fuel just goes through the rails and back to the tank....dont know how much fuel pressure i do have ......

The engine does crank strong but there is not even a little firing..

Hope u can help me once again

Thx
Achim