The CMFI or CSFI component tightly controls fuel supply in the engine located at the lower intake manifold center. Among other features, a CMFI system has an adjustable aluminum air intake plenum and one non-serviceable fuel injector unit; while a CSFI system comes with non-adjustable air intake plenum, six individually controlled fuel injectors and it incorporates a Mass Air Flow sensor. The PCM tracks various engine parameters by means of sensors and energizes the fuel pump briefly upon ignition. Fuel is delivered into cylinders via poppet nozzles in tubes by a high-pressure electric pump found inside the tank of the fuel regulated by a pressure regulator of fuel. This is accomplished by an Idle Air Control valve that regulates additional air flow. Multiple steps must be taken for upper intake manifold removal such as disconnecting battery, relieving fuel pressure, removing components as well as disconnecting different connectors together with hoses. Installations are done inversely to their removals. A similar procedure which involves disconnection of battery, relief from pressure on fuels and also taking away related components is used to remove CMFI as well as CFIS fuel injection units (CMFI). Fuel Injectors are inspected for faults and replaced if necessary. Idle Air Control (IAC) Valve checks resistance and operation during idle speed control checkups. Several steps for removal and installation including resetting IAC Valve are provided in this respect. Intake Manifold Tuning Valve (CMFI) must be checked for replacement when necessary. Fuel Injector Replacement (CSFI) calls for detachment of the fuel meter body from its installation place back again into it after fixing it up (CSIF). The Fuel Pressure Regulator (CSFI) would be replaced following o-ring replacement among other specific steps. Throttle Body Removal/Installation (CSFI): Disconnect various components , ensure proper cable operation etc. In details, Throttle Position Sensor (TPS) checks involved backprobing, removal of mounting screws and alignment during installation.
