Originally Posted by
GVK.
I have replaced cam sensors on zetec se before, but they have always been runners, just logging a fault with MIL on.
On some engines they won't start with a bad cam sensor as the ECU is not seeing engine 'synch', but you can unplug them whilst running and they will continue to run.
That's exactly what happens with the old Weber management.
Although the later versions use battery voltage as part of an algorithm to determine the phasing, in the event of the sensor failing, which I assume is what all the modern ECUs do.
Martin