Starting and boosting problem

1. Vehicle does not start when cam sensor is plugged in.
2. Disconnect the cam sensor, motor starts and idles.
3. Connect cam sensor, motor shuts off.
4. No cam sensor vehicle mobile in limp mode.
History.
motor overheated and busted the cylinder head.
New head fitted
new oil pump.
motor re done (rings, bearings).
timing set again, both front and clutch flywheel.
no electrical problem diagnosed by Nissan dealer.