A method for estimating pump torque of a computer-controlled fuel injection heat engine for a motor vehicle. The method determines the pumping torque in a for of a relative pumping torque representative for total pumping torque contribution of an intake and exhaust valve system, wherein the relative pumping torque is determined by a relation factoring in engine cubic capacity, a pressure difference, an exhaust pressure differential estimation due to the presence of the exhaust valves, and an intake pressure differential estimation due to the presence of the intake valves.