Is the injector putting in any fuel at all?
Take off the injector plug for this cylinder, then test with a meter for voltage... on 1 of the pins, there should be a constant +12v supply (with the other meter probe to ground)... and the other pin should have continuity to Pin 101 on the ECU plug.
If both are ok, then its possible the injector is duff... can test resistance of the injector between the 2 pins... should read ~13-14 Ohms.
If the injector is ok, then either the spark is poor (bad plug or CP) or missing, or it could be a compression problem with the cylinder.