With continued cranking, voltage may have dropped below the minimum threshold required in order for the ECUs to work. During cranking, the ECUs MUST see a minimum of about 10.5v or they won't work. Hence, either no spark or no fuel. Check cranking voltage first.
The flywheel has a magnet on it that results in the sensors inducing a signal that goes to the ignition ECU. With this and other inputs, the ignition ECU then calculates when to make/break the ignition coil ground circuit that will produce high voltage from the coil at the correct time. It's possible that the magnet got buggered during the repair. Please have a look here
to see where the timing mark and magnet are on the flywheel. I'd think it would be possible to put the engine on TDC #1, remove the top sensor and look at the magnet (although I've done it).