Cold Start System: Maxima
The cold start system provides additional air and fuel during cold engine starts. The cold start system consists of the following: Auxiliary air valve which provides additional air, cold start injector which delivers additional fuel, and a thermo time switch which controls operation of the cold start system.
The thermal time switch has a bi-metallic contact surrounded by a heating coil which is energized during engine cranking. This switch limits cold start injection to 1-12 seconds under extreme cold engine starts in relation to engine temperature. When engine temperature rises above a specified point, bi-metallic contact breaks ground circuit of cold start injector and cold start enrichment is by-passed.
The auxiliary air valve provides additional air during cold engine starts and warm-up periods. The valve consists of an electrically heated bi-metallic strip, movable disc, and air by-pass channel. The heater coil on the bi-metallic strip is energized by the fuel pump relay. Control of the valve is based upon engine temperature; the air by-pass channel is open when engine is cold and gradually closes as temperature rises. At predetermined temperatures, air by-pass channel is blocked and additional air flow stops. See Fig 1.