Hummer 12609749 Sequential Multiport Fuel Injector Assembly

To remove the upper intake manifold, first disconnect the negative battery cable and relieve fuel system pressure. Disconnect various electrical connectors, including those for the EVAP canister purge solenoid and MAP sensor, and remove the PCV crankcase ventilation hose. Remove the upper intake manifold mounting bolts and throttle body mounting studs, and discard the old gasket. To remove the fuel pulsation damper, remove the retaining clip and pull it out of the Throttle Body, then discard the old o-ring. To remove the throttle body and injectors, remove the fuel supply line and various seals, detach the injector poppet nozzles, and remove the injector retainer nuts and retainer. Installation for all components is the reverse of removal, using new gaskets and o-rings where necessary and tightening fasteners to proper torque specifications.

First, remove the intake manifold cover to get it off the fuel injectors on a vehicle. It is also necessary to relieve the fuel system pressure and disconnect the negative battery terminal cable. After that, air intake and manifold cover bracket bolts are removed as well as the nut holding engine wiring harness bracket to intake manifold. Electrical leads in engine wiring harness traced and disconnected from various components including alternator, EVAP purge solenoid, ignition coils, MAP sensor and throttle body. Also, electrical connectors from fuel injectors were disconnected; engine wiring harness clips were detached too. The PCV hose is disconnected from the intake manifold while the fuel line is disconnected from the fuel rail. The EVAP canister purge solenoid is removed from the intake manifold while the fuel rail mounting bolts are removed. Thereafter, injectors are disengaged from engine as an assembly through lifting them out of top of intake manifold by each individual injector retainer with its old o-ring removed.New o-rings should be installed after which they are lubricated with clean engine oil before reassembling both injectors and fuel rail. This process however must be done in reverse starting by tightening up of fuel rail mounting bolts and then pressurizing of fuel system so as to ensure there are no leaks occurring during installation.

After removing the intake manifold cover, the fuel system pressure needs to be relieved and the cable from the negative battery terminal needs to be disconnected.