End float has been checked and is within spec. As I say, it does look like the engine has been reconditioned and I'm sure the clue lies therein. If we either disconnect the crank sensor plug or leave it plugged in but not located, the engine starts and runs fine. Its only when the sensor is picking up a signal that it wont start. If the crank has no TDC reference how does the ECU know that something is wrong and prevent it from starting? It must only use this signal as a speed reference and not timing....