(57) A method for improving fuel control in an internal combustion engine employs a pressure ratio to determine the engine's actual volumetric efficiency continuously as the engine is operating. The air fuel ratio of the engine's combustible mixture is affected by the volumetric efficiency. The volumetric efficiency varies during engine operation. Determination of the actual volumetric efficiency on a real-time basis allows greater accuracy in fuel metering. The pressure ratio used in the determination of the volumetric efficiency is the ratio of the intake and exhaust pressures or the inverse of this ratio. The ratio of pressures is combined with a second factor representative of the forces acting upon the air or air fuel mixture inducted into the engine. The pressure ratio may be obtained without actual measurement of the pressure in the engine's exhaustconduit.