kia stortage cam sensor
 

Dear all,
long story short, I am trying to fit Sportage motor in NB bed. I have a Mega 1 with previous engine up-and-running. Now I am trying to fit the camshaft sensor (0K0131813X). the result is I cannot get pulses on the signal wire.
1. this sensor has a magnet inside and 3 wires, according kia's manual (B+,signal, gnd)
2. exhaust camshaft has a pin that is passing on more than 4mm (!?!?) in front of the sensor. I got a salvage cylinder head and the sensor is from previous head (same distance to the sensor).
3. I had removed the sensor from the head, and if I pass with tin screwdriver on the head of the sensor I am getting 0v on the signal. this is happening if the gap is less then 2mm.

Any clue?

this sensor new is more than 150$ ;(. Is it possible sensor to get tired and lose sensitivity, I do not want to buy a new one and being in the same situation.
better to drill and replace with other than to give 150$ to a local dealer.