I’m very familiar with these systems and the reason for no injector spray could be due to any one of a number of reasons. This is all assuming the fuel pressure is correct. CIS is very, very touchy about system pressures, warm and cold control pressures, etc.
A specialized tester is needed to check those pressures.
Stuck pressure regulator, stuck fuel distributor plunger, air leak or leaks, and stuck air sensor plate are some of the reasons.
VW CIS is prone to air leaks around the fuel injectors. Whether the seals and injector seats are bad enough to cause this problem with your particular car I do not know.