The advantages of common rail direct injection engine, including more power, less noise and vibration, lower specific fuel consumption, precise injection timing and control over the mass of fuel injection, make the engine more popular and adoptable in all the transport vehicles by the automotive manufacturers across the world. The production and use of dairy products across the world is increasing rapidly and much of the scum obtained during the processing of dairy products is unused and discharged to atmosphere as a waste product which further leads to an adverse effect on the environment and grubby surroundings. The present study aims to use the dairy scum methyl esters in common rail direct injection engine for its adaptability and evaluate the engine performance in comparison with diesel fuel. Injection pressure is primarily the vital factor which persuades the performance of the engine, as the atomisation of the fuel depends on it. Hence, in the current study the injection pressure is augmented in the range 600–1000 bar by keeping the injection timing stable. The results revealed that the augmentation of pressure curved to raise the brake thermal efficiency and lessen the emissions.