In the present experimental investigations the influence of injector opening pressures and injection timings on the engine performance and exhaust emissions of a naturally aspirated single cylinder diesel engine has been investigated. The test were conducted with four different fuels, namely diesel and Tung biodiesel blends (TB10, TB15, TB20 and TB50) at three different injector opening pressures (150 bar, 200 bar and 250 bar) respectively. Fuel injection opening pressures were varied by changing the spring tension of the needle valve of injector nozzle. The three different injection timings (Standard timing at 23° BTDC, Retarded Timing of 21° BTDC and Advanced Timing of 25° BTDC) were used. The injection timings were varied by changing the thickness of the shim. The entire tests were conducted at the constant engine speed of 1500 rpm under various load conditions. The experimental results showed that brake thermal efficiency (BTE) of Tung biodiesel improved at higher injector opening pressure. BTE of the engine increased with the advancing the injection timing for the test fuels. At higher injector opening pressures CO, HC, smoke emissions reduces significantly for all test fuel but NOx increases. At advance injection timing, brake specific fuel consumption (BSFC) and NOx increases. At advance injection timing, smoke emissions were observe to be reduce but increases with retarded injection timing.