This article investigates the effects of injection timing, injection pressure and compression ratio on performance characteristic (brake thermal efficiency) and emission characteristics (smoke, HC, CO and NOx) of a single-cylinder direct injection diesel engine when fueled with Honge oil methyl ester (HOME). The experiments were planned as per full factorial design (FFD). The relationships between the process parameters and the various characteristics have been established by developing second order mathematical models using response surface methodology (RSM). The analysis of variance (ANOVA) was performed to check the adequacy of the proposed models. The RSM based parametric analysis reveals that retarding the injection timing improved the performance of diesel engine fueled with HOME in terms of increased brake thermal efficiency and reduced emissions. (C) 2012 Elsevier Ltd. All rights reserved.