FFVs are specially designed to run on regular unleaded or any ethanol fuel blend up to 85 percent. Special on-board diagnostics “read” the fuel blend, enabling drivers to fuel with E10, E15, E20, E30, E40, E50 or any ethanol blend up to E85, or regular unleaded if E85 is not available. Therefore, any part of the engine which comes in contact with the fuel has been upgraded to tolerate alcohol. Normally, these parts include an upgraded fuel system with alcohol compatible parts. Today, Chrysler Corporation, Ford Motor Company, General Motors, Nissan and Toyota all offer flexible fuel engines as standard equipment in certain vehicles — at no additional cost to consumers. Each FFV comes with the same factory warranties as gasoline vehicles.
The significant difference is the fuel sensor which detects the ethanol-to-gasoline ratio. A number of other parts on the FFV’s fuel delivery system are modified to be E85 compatible. The fuel tank, the fuel lines, fuel injectors, computer system and anti-siphon device have been slightly modified. Alcohol fuels can be more corrosive to certain metals than gasoline; therefore, fuel system parts have been upgraded for high level ethanol use.