The use of biodiesel is under evaluation as a possible fuel alternative to fossil fuels. Despite the literature available concerning the effect of biodiesel on engine performance and emissions under steady operation, there are not many research studies which cope with the effect of biodiesel during transient operation. Moreover, it is interesting to study the repercussions that the use of biodiesel has on complete vehicle performance and emissions. In this sense, the part 1 of the present paper deals with a preliminary analysis where the test facilities and procedures are explained, and the effects of the physicochemical properties of biodiesel on fuel injection are studied. To cope with the repercussion of the use of biodiesel in engine emissions during the MVEG-A cycle in this part of the paper a deep analysis of the pollutant emissions obtained during tests is done. Based on this analysis the paper also presents an approach to improve the engine control calibration to take advantage of utilising biodiesel. (C) 2009 Elsevier Ltd. All rights reserved.