The present disclosure relates to an engine provided with cylinder deactivation (“CDA”) apparatuses for at least some engine cylinders and provided with a water pump, and a method for controlling the same. The method for controlling the engine includes a controller: determining, based on output signals from vehicle driving information sensors, whether or not a current vehicle driving state corresponds to a CDA driving region; operating CDA apparatuses of some of the cylinders when the current vehicle driving state corresponds to the CDA driving region; determining whether or not detonation border lines (“DBLs”) of respective cylinders the CDA apparatuses of which are not operated precede a minimum spark advance for best torque (“MBT”); and, when the DBLs precede the MBT, operating corresponding water injecting nozzles so as to inject water into the respective cylinders.