86 mercedes 300e fuel

[SIZE=3][B][FONT=arial][COLOR=crimson] I am replacing a 3.0 liter 6clinder engine in my friends MB.[SIZE=1] This is my first time with MBs, and I have both the tech manual and the "Owners Bible".
1. Fuel goes into the distribution center but nothing coming out the injectors.
2. What is the PSI rating for fuel system and how do I tell if a fuel regulator is bad?
3. How do I know if the ECM is screwed?
4. How do I test the PCU valve?

Any help would be much appreciated,

Ron's mechanic, MIKE