Environmental concerns and rapid depletion of fossil fuels have caused interests in the study of alternative fuels for internal combustion (IC) engines. For internal combustion engines, ethanol fuel is receiving more attention because they are biodegradable, oxygenated and renewable fuels. This paper presents the experimental investigation to study the effect of fuel injection timing and intake air temperature using pure ethanol blended biodiesel fuel (B5E15), on the combustion and emission characteristics of a single cylinder, four-stroke, air cooled, direct injection diesel engine. The tests were carried out using B5E15 fuel under constant speed (1500 rpm) and load (2 kW) with different injection timing (12, 15, 18, 21 and 24° CA bTDC) and different intake air temperatures (40°C and 60°C) at 1.1 bar intake manifold pressure. The combustion and emission characteristics such as in-cylinder pressure, temperature, heat release, NOx, UHC, CO and smoke are presented and discussed. The experimental results reveal that advancing the injection timing results in increase in-cylinder pressure, temperature, heat release rate and NOx emissions. In addition, the CO and HC emissions exhibit a decreasing trend according to an increase in the intake air temperature and advance in the injection timing. The preheated intake air favours premixed combustion, resulting in increased peak cylinder pressure and heat release rates. © 2013 The Authors. Published by Elsevier Ltd.