GM 19110532 Throttle Body Fuel Injector

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.

For a non-adjustable TPS output check, connect a digital voltmeter from center terminal "8" to outside terminal "A" of the TPS connector. With the ignition on and the engine off, the TPS voltage should be less than 1.25 volts. If the voltage exceeds specifications, replace the TPS.

To maintain the IAC valve, you should unplug its electrical connector, remove the valve, discard the old IAC valve gasket, clean the throttle body surface, and check the pintle dimensions.

Yes, you need to remove the air cleaner housing assembly, adapter, and gaskets.

To replace the throttle body, first, remove the air inlet duct and disconnect the wiring connectors from the Idle Air Control (IAC) valve and Throttle Position Sensor (TPS).

All open fittings, lines, and holes must be capped or plugged to prevent dirt from entering the system when any components are removed. Additionally, when replacing components of the fuel rail and injector assembly, fuel injectors are calibrated with different flow rates and must not be interchanged with injectors from a different application.