Red Line 60103 SI-1 Fuel System Cleaner - 15 oz.:SI-1 injector and valve detergent is a concentrated package of the most powerful high-temperature detergents available to clean gasoline fuel injectors or carburetors, intake valves and combustion chambers and can clean injectors to nearly 100 percent efficiency in one treatment. The cleansing effect on injector deposits can raise fuel economy approximately 12 percent or even greater, depending on the condition of the injectors.