[twobjshelbys]

You don't say which DFI controller. Assuming that it is the Accel DFI system.

Try a new coil. It's a quick and relatively cheap swap. If that doesn't do it check your MSD (or other electronic) ignition box. They have a test procedure - you can't simply short a plug wire or the distributor feed.

It is most unlikely but not impossible that the DFI controller itself is at fault. If you have an oscilloscope probe the ignition wire from the DFI controller to the MSD. You should see it pulse. It is a 12V signal so you won't hurt the scope. Under no circumstances probe the output of the MSD to the coil.

You can get the wiring diagrams for these from the Accel web site.

Mine turned out to be the MSD. It just died.

FYI, I don't know about yours but on mine the coil is attached to the engine. I don't like that location and wires were too short to relocate it so bought a high-vibration coil even though the coil was still OK.