Pine oil biofuel is unique in that the feedstock originates from forest and can be blended with petro-based diesel fuel in higher percentages because of its distinct physical and thermal properties. The feedstock, which is obtained from the oleoresins of pine tree, has been endowed with lower viscosity and boiling point than diesel. Though pine oil is found to have comparable calorific value with diesel, the lower cetane number of it affects the ignition process and in order to address this, in the current work, an attempt to preheat the inlet air has been made to provide necessary support for the self-ignition of pine oil. In this regard, an external heater had been mounted in the inlet manifold and the temperature of the inlet air was heated from 40°C to 70°C in steps of 10°C, while pine oil was injected as neat fuel through the main injection system. From the experimental investigation, it is reliably learnt that 60°C was ideal temperature of preheat; wherein, pure pine oil showed comparable performance with diesel. By the same token, the engine out emissions were also found to be reduced, with a notable decrease in CO and smoke emissions by 46.2% and 38.9% respectively than normal diesel fuel operation..