This paper presents the results of a parametric study on the effect of varying the fuel injection pressure of a turbocharged multi-cylinder heavy duty off-highway diesel engine. The study is based on one-dimension engine models simulated in AVL BOOST™ engine simulation software. The base engine model has been validated using performance data from test bench. The fuel injection pressure has been varied and the start of injection has been swept at each injection pressure and speed. As a result, a collection of data has been obtained from which the injection pressure and the start of injection for the most efficient engine performance would be obtained as a function of speed. The generated data could serve as an input for detailed CFD simulations for further optimisation. © Published under licence by IOP Publishing Ltd.