5.3 knock/cam sensor not connected

[Slowy-gonzalez]

I had done one of this swaps about 10 yea4s ago, however I recently bought a truck that swap was done by someone else.while it seems like they put some quality stuff as headers, trans controller, hid the wires etc etc , i removed the intake today and i notice the sensor on the rear of the engine is not connected nor it was connected ever since there is no wire connector going to it. The truck runs very good and strong but how is this possible? The harness is not hooked up to a oem ecm. Instead it has a aftermarket engine module, but I thought the sensor was needed for the engine to actually run. Any ideas