to be honest i wouldn't worry at all about the accumulator or fuel pressure or any of that at the mo.. if all you have had done is the engine rebuilt, then it will be something actually on the engine... providing the car ran ok before the re-build..
I would make sure all the boost pipes are connected properly, all the wiring plugs are on and the leads are in the right order. where in the world are you ?? is there no-one close that could have a nose at it for you??