An illustrative fuel delivery system for an engine can include a fuel type indicator device and a flow management device. The flow management device can be configured to receive fuel from an auxiliary fuel tank and to direct it based on the type of fuel in the auxiliary fuel tank. If the type of fuel in the auxiliary fuel tank is a primary fuel type (such as diesel or gasoline), the flow management device can deliver the primary fuel to a piston cylinder of the engine. If the type of fuel in the auxiliary fuel tank is an auxiliary fuel (such as a mixture of ethanol and water the flow management device can deliver the auxiliary fuel to an air intake system of the engine.