Renewable energy sources are attracting more attention due to lower cost and lower pollution relative to fossil fuels. The aim of this experimental work is the production of renewable and clean methyl ester from pomace oil as an alternative fuel. This oil was obtained from pomace which is the waste of olive oil plants. optimum producing conditions were determined experimentally. The maximum yield was obtained at 30% of methanol/oil ratio, 60 degrees C temperature for 60 min with NaOH catalyst. The properties of the biodiesel thus obtained were compared with diesel fuel requirements. An organic based Manganese additive improved the biodiesel properties. Doping the fuel at a ratio of 12 mu mol/l oil methyl ester led to a 20.37% decrease in viscosity, 7 degrees C fall in the flash point and reduced the pour point from 0 degrees C to -15 degrees C. This blend of pomace oil methyl ester-diesel fuel with manganese additive was tested in a direct injection diesel engine. The maximum effect of the new fuel blend and diesel fuel on engine performance was obtained at 1400 rpm. (C) 2008 Elsevier Ltd. All rights reserved.