Car suddenly would not start after replacing the valve cover gasket?

Car suddenly would not start after replacing the valve cover gasket and camshaft sensor. I tried putting the old camshaft’s sensor back on but still no start. It appears to not have a spark. More info: I recently replace the turbo, timing chain and radiator, but the car ran fine for 1000 miles (there was a steady check engine light on). Then decided to redo the valve cover gasket and camshaft sensor (due to oil leak and bad O ring) at that point it would not start again. My code reader showed P2245 (O2 sensor low voltage) and also P2119 (throttle actuator control). I replaced the throttle body at that point and the P2119 code went away, but then showed a P0340 (camshaft sensor).