I finally got a chance to put a lamp on the #1 cylinder injector cable and disconnected the camshaft position sensor and crankshaft position sensor in turn.

Camshaft sensor connected..crankshaft sensor connected..flashing light
yes................................... yes.................................... yes
no.................................... yes..................................... yes
yes................................... no....................................... no

Is a cylinder head overheat likely to toast a camshaft sensor?
Am I correct in thinking that signals from BOTH camshaft and crankshaft sensors are required in order to fire injectors?