TFI gets power from the high side lines to the injectos, and ground from the ground lead. Two TFI leads plug into the injector wires, that you disconnected from the injectors. This feeds the injector power and drive signals to the TFI. Two other leads go to the injectors, to drive them. The TFI passes the ECU's injector drive right through to the injectors, and also pulls the injector drive lines for a bit more time, after the ECU lets go. Beautiful design. Simple from the outside (operator/installer view), not so much on the inside (sophisticated load determination algorithms).
If no lights at all, I'd say that either you have not connected your TFI ground, or you have not connected your stock injector leads into the TFI.
Just a guess...
Enjoy,
Rich P