I had the same problem yesterday,i don't own a cosworth but my car's fitted with Pectel super 8.
Check the phase sensor wires carefully,mine had both snapped inside the rubber boot resulting in no spark...
1 other quick way to check to see if the wiring is ok is to turn on the
ignition and disconnect the plug to the phase sensorthen re-connect the connector,the pump should prime,same thing goes for the CS,if a lug passes the sensor it should fire the pump and click both relays.