An engine control system for a vehicle includes an oxygen mass flow rate module, an oxygen per cylinder module, and a fuel control module. The oxygen mass flow rate module generates a mass flow rate of oxygen flowing into an engine based on a mass air flow rate (MAF) into the engine and a percentage of oxygen by volume measured using an intake oxygen (IO) sensor in an intake system. The oxygen per cylinder module generates a mass of oxygen for a combustion event of a cylinder of the engine based on the mass flow rate of oxygen flowing into the engine. The fuel control module controls fueling to the cylinder for the combustion event based on the mass of oxygen.