Air Flow Control

During engine idle, the throttle valve is almost completely closed, so it is necessary for the idle air by pass to supply air for combustion during idle. An air adjust screw is installed in the idle air bypass to adjust intake air flow for idle speed adjustment. During off idle operation, the throttle valve controls the amount of air admitted into the engine. The ECA will increase fuel injection output in proportion to the increased air flow to achieve the appropriate air/fuel ratio.