Polo 19 tdi don't start with new camshaft sensor if plug out it starts

SOURCE: camshaft sensor

Do you know if the engine timing is correct? If you get the timing a tooth out you very similar issues, has the cambelt been replaced recently - or is it over due??
Another posibility is the cam chain adjuster. This is oil pressure fed and I think controled by a solnoid, it applies a force between the chain that drives the inlet camshaft from the cambelt driven exhaust camshaft. (Making any sense? Let me know if you want me to simplify) This operating correctly advances and retards the valve timing, when faulty it can make it incorrect. Non start is a fault caused, but more often they become very noisey.
The cam chain adjuster is fed oil when the car is started, you can breifly here it before it has reached operating pressure on normal start up, sounds like a diesel knock for a second, then goes, this is normal. If it continues, its more than likely faulty.
Let me know if you want any more info. If the sensor and wiring is good you'll probably have a timing issue.

SOURCE: I have a 1998 plymouth voyager with the 2.4l 4

Sounds like the cam shaft is not timed properly and the sensor is doing it's job

SOURCE: 2004 nissan sentra bad camshaft sensor, replaced

I am having the exact same problem. Did you get it running

SOURCE: can a speed sensor failing cause my Peugeot 307

an approved/competent peugeot dealer with peugeot diagnostic equipment can connect it to your vehicle and check the signals from the camshaft and crankshaft sensors. there shouldn't be any doubt about it. the engine control unit(ecu) needs both sensor readings(to identify which cylinder to inject fuel into)before it can start. a new cam sensor has a plastic nipple which should be in contact with the target plate when first fitted, this brakes off when the engine is started. it is used to ensure the correct gap between sensor and target plate. to large a gap and the sensor may not work correctly. once engine is started this info' is ignored by the ecu. the fuel pressure(measured by another sensor) can also be checked and is displayed on the equipment in "bars". 250bars of pressure are needed for engine to start. one of these (cam, crank, or fuel pressure signals) must be wrong if engine is not starting(assuming uncontaminated fuel). which one determines diagnostic path to be followed. 

SOURCE: My 2004 hyundia Santa fe won't start it just die

Check fuses under the hood. When the crankshaft sensor shorts, it often blows this fuse. It is a 10 amp fuse. I don't remember what number it is off hand but it will be efi related.