I had a similar problem on my Vw twin cam turbo 2.0 16v engine i fitted Pectel super 8 injection on, for some strange reason that i never worked out why no.3 injector on the second rail every now and then used to jam open! quite dangerous as the cylinder filled with fuel in seconds.
I was using Weber beige 385cc disc type injectors at the time so changed to Bosch 380cc orange jobs and the problem went.
Have you tried disconnecting the fuel rail along with injectors aimed into jars and statically spraying the injectors with the ignition on and crank sensor aligned? both relays should click and the injectors should fire, no need to crank the engine just turn the crank by hand on its pulley.
When the injectors spray how much fuel comes out?