Injector Questions!?!?!?!?

[tex_waco_usmc]

OK so as you all know I have been pounding my head against the wall trying to figure this 01 F350 out. Finally stepped back today and took a methodical look into it. Eventually after checking GP's and fuel, I got to the injectors. After putting a Noid Tester on the injector harness I found that I was not getting a signal to the injectors for them to fire. So my question:

Can someone explain to me how the injection system works so I can backwards troubleshoot from the injector?

Does anyone know right off the top of their head what might cause the injector signal not to be there? Maybe someone has had this problem in the past?

[greasyF250]

check out this link , it will help you to trouble shoot the injectors and connections.
http://www.gbreman.com/docs/techbull...eplacement.pdf