Sunflower oil methyl ester is one of the edible, sustainable and renewable biodiesels, which has a high potential for its production worldwide. Globally, the cost and demand are increasing for diesel fuel. SOME can give a better alternative fuel for related problems associated with the utilization of diesel. Experiments were conducted to determine optimistic operating conditions for the biodiesel SOME to enrich its performance characteristics and reduce the magnitude of its emission characteristics than those observed at initial operating condition of 250 bar injection pressure with injection timing of 23° before-TDC. Hence, experimental trials were performed to evaluate characteristics of SOME (such as performance, combustion, and emission) by varying its ignition delay period through varying IPs like 500, 625, and 750 bar via making wide variations in the ITs such as 8°, 13°, 18°, 23°, 28°, and 33° before-TDC at 1500 rpm speed with compression ratio 18 at full load condition. For the SOME, it is investigated that IT 23° before-TDC at 250 bar IP is an optimistic operating condition for better performance and lower level of emissions. At this optimistic operating condition, it is observed that SOME give a minor amount of hydrocarbon (HC) exhaust emissions (0.01 g/kW-hr), whereas its nitrogen oxide (NOX) exhaust emissions were 45% lower than diesel. The ignition delay period has decreased when the IT condition shifted towards TDC position.