I replaced the head gasket on my daughters 760 turbo and cannot get the car to start.
1)Good compression..approx 100 lbs all cylinders
2)Timing belt and cam timed properly,new rotor cap and plugs...checked several times with mechanic friend
3) Spark at all cylinders....checked with spark test light and timing light.
4) Good fuel delivery and injectors are getting pulsed...checked with noid light.

I have read here if tach does not jump when cranking then suspect hall sensor. My tach lies dead still while cranking. Is this possible and still have spark?

I have checked timimg mark while cranking and the pulley mark is off the scale at approx 20 degrees after TDC. I have to rotate the distributer way past its normal position for lock down to get light on 12 degrees btc. Is this normal while cranking? The correct timing is 12 degrees btdc yes? Does the 12 degree setting come into play only after the car is running?

So, I have spark, fuel, compression and confident the engine is mechanically timed properly.
Could the hall sensor( since it lies dead during cranking) cause the timimg to walk?
Also, the engine will try to start upon 1st crank of the day,then just go to a crank no start for the duration.