In this paper, the sound intensity and airborne source quantification methods were used to estimate the airborne noise radiating from a gasoline direction injection engine and the contribution of gasoline direction injection engine components to such airborne noise. In order to estimate noise contribution using airborne source quantification, the volume velocity for source should be estimated. In the previous method, the volume velocity has been estimated by using the inverse method. In this paper, the volume velocity is estimated directly. For this work, the sources of noise radiating from the engine are first identified by measuring the sound intensity of the noise sources while the car's engine is running at idle condition. The volume velocities of these sources estimated by multiplying the area of that noise source and directly measured particle velocity. In order to validate the proposed method, two speakers with different frequencies were installed in an anechoic chamber and the contribution of each source was estimated. Finally, the proposed method was applied to the identification and contribution of noise sources in a gasoline direction injection engine.