Injectors not operating after rebuild

Morning all,

I've just renewed the piston rings in my 1.8 duratec (2004 Focus Cmax). Carefully reset the timing, and replaced everything as it was, taken my time and triple checked everything. However, although it cranks over fine, and the spark plugs are operating (will fire on a quick burst of easystart), it wont run normally. There is fuel in the rail at pressure (found out the hard way!)

I'm wondering whether the crank position sensor might be the culprit - I refitted it as before, but of course with the pulley being removed, there might be a nadger of a difference in its setup.

Does this sound like a good place to start, or is there something else I should look at?

Thanks

Gary