91 b2600 no spark on coil

ok i have surfed and surfed and i have come up with nothing for my problem..
I have a 91 b2600i that i can not get any sprk from the coil i have went to a salvage yard and pulled the ecm coil ecm wireharness plus multiple other parts from a truck there i still get no spark. i am wondering if there is any one who can gie me some pointers. I have checked the resistance on the coil and everythign seems to be within spec i am really trying to avoid spending 3 or 4 hundred bucks replacing parts hoping it will fix it. so if there is any way to test the capaciter that is for radio interferance or anything else i can test that would be great.

thanks

Are you getting signal to the coil? Your timing components are intact right? i.e. timing chain and gears