Abstract The use of palm oil-based biodiesel fuel has been proposed as an alternative fuel for diesel engine in Malaysia. The purpose of this study conducted by UTM is to investigate the combustion of various blends of palm oil products in a small-unmodified direct injection diesel engine, and compare it to that of a conventional diesel fuel. Experimental measurements of engine performances, exhaust emissions, cylinder pressure and rate of heat release were performed as a function of engine load for different engine speeds. It was found that in general, the palm oil-based biodiesels behaved comparably to the reference fuel in term of performance and rate of heat release. Smoke density readings show improvements as compared to that emitted by the diesel fuel in which operating under similar conditions. The results of carbon monoxide (CO) emissions were varied and nitrogen oxide (NOx) emissions were strongly related to the cylinder pressure development. The results of performance and emission on the single cylinder engine can be summarized as promising and are described in the paper.