Fuel Injector Resistor: Description and Operation

The injector timing, which controls the opening and closing intervals, must be accurate since it determines air/fuel mixture ratio. For ideal injector response, it is necessary to shorten current rise time when voltage is applied to the injector coil. Therefore, the number of windings in the injector coil is reduced to reduce inductance in the coil. This lowers coil resistance, allowing a large amount of current to flow through the coil. As a result, the amount of heat generated is high, which decreases durability of the coil. Flow of current in the coil is restricted by a resistor installed in series between the electrical power source and the injector coil.