look at the fuel rail pressure data PID on your scan tool, you should have around 200 to 300 bar cranking.
if not then you have a supply problem, or a pump problem, or more likely a injector problem,
have a read here for a over view,
https://personel.omu.edu.tr/docs/ders_dokumanlari/894_52413_1913.pdf work out what system you have and then start testing, cracking injector pipes and looking for pressure is a waste of time, use your scan tool and follow a set diagnostic path,
or send it to a diesel specialist