Although the motoring measurement method is generally used in comparison of engine friction losses, the condition of motoring engine is different from firing engine. Furthermore, in order to evaluate friction losses in each part of engine component, the firing measurement method in crank angle domain must be required. Therefore, the firing measurement method for total engine friction loss has been improved. This method is based on the fact that fluctuation of angular velocity in crankshaft system is related to indicated, brake and friction torque variation. Finally, this technique is applied to new diesel engine to confirm the reduction of friction losses.