In this paper the influence of some parameters in the operation of a ramp pump is studied: delivery valve spring, pressure chamber volume, stroke of the delivery valve and the ratio of the delivery valve area to the waste valve area. Experimental studies are performed in a dedicated test bench for this purpose. Additionally, an analytical model is proposed and validated using experimental data. The developed model allows to extent the study of the ramp pump including a specific analysis of the delivery valve. Based on experimental and theoretical results can be concluded that the delivery valve spring and the ratio of the delivery valve area to the waste valve area affect significantly the ramp pump efficiency. On the other hand, the pressure chamber volume does not represent significant influence on the efficiency of the ramp pump.