Thank you for your reply as well the other guys. I connected the sensor on my arduino and with the help of serial sketch i saw values for metal object lower than a volt. When i moved a magnet at the tip of the sensor i reached 4 volt signal. In both situations i directly connected the pins to my ground and input of my arduino and moved the magnet and metal by hand as quickly as i could do to see the range of volts it produces. I believe that the sensor was ment to detect teeth and not magnet object because at 3500 top rpm of camshaft is going to make serious voltages that could fry the original circuit.
If you were measuring the voltage with a meter with several megohms input resistance, I can see where you might get such a voltage. Load the sensor with a resistor of 1000 Ohms or so and see what you get.