you said it's LIKE the ecu isnt getting power or ground, have you check to see if it was? (that part was kind of vague, you said you checked the grounds)

have you rechecked your dpfi to mpfi wiring? im not sure if your post is a little vague about it, or if you wired the crank angle sensor wires improperly.

do the injectors have power or are they getting a pulsed ground signal?