Start by relieving system fuel pressure and disconnecting the battery's negative terminal to perform maintenance procedures on the throttle body assembly. After that, take off the air cleaner housing assembly, adapter, and gaskets. Regarding the Fuel Meter Cover/Fuel Pressure Regulator Assembly, unplug the electrical connectors to the fuel injectors and remove both long and short fuel meter cover screws, to allow for removal of fuel meter cover. Then take out the cover if there is any dirt on it; additionally one should replace such seals as a fuel meter outlet passage gasket, pressure regulator seal or a cover gasket and then clean up its surface if necessary. Eventually install new gaskets and seal as well as put back the fuel meter cover assembly having used Loctite 262 on all screws. Reinstall the electrical connectors to injectors together with battery cable while checking for leaks with engine off and ignition on prior to reinstalling the air cleaner housing assembly along with its adapter and gaskets. In case of Fuel Injector Assembly unconnect electrical connectors from fuel injectors, remove Fuel Meter Cover/Pressure Regulator Assembly and using a screwdriver gently take out them from their seats. The injector consists of upper O-rings, lower O-rings as well as filter which need inspection for dirt or contamination after being removed from an injector; therefore, use another part including an identical replacement injector while sliding in a new filter then lubricating or installing new O-rings before pushing it into a fuel meter body. When replacing an IAC valve, make sure that you unplug its electrical connector before undoing it with an adjustable wrench. Take away old IAC valve gasket that should be discarded afterwards leaving throttle body clean while making measurements at different pintle positions. Finally adjust pintle if required after putting back new gasket before returning IAC valve completely for correct torque specifications when installing it. Reconnect the electrical connector and install air cleaner housing assembly, adapter and gaskets. As for the Fuel Meter Body Assembly, disconnect electrical connectors from fuel injectors and remove Fuel Meter Cover/Pressure Regulator Assembly, Gaskets and Seals. Remove the fuel injectors, unscrew the fuel inlet and return line threaded fittings, detach lines with O-rings removed. After removing the fuel outlet nut or gasket as well as the inlet one, put on a new throttle body-to-fuel meter body gasket then place the fuel meter body assembly via throttle body. Before tightening these screws to not forget to apply thread locking compound on them; thus use thread locking compound on the attaching screws of the fuel meter body-to-throttle body assembly. Install new gaskets as well as inlet-outlet nuts followed by installing it with a new TBI-to-manifold gasket and new O-rings on fuel line nuts. The air cleaner housing must be reinstalled together with adapters, gaskets. Finally, unplug all electrical connectors; remove the throttle linkage, return spring(s), transmission control cable (automatics), cruise control if equipped, detach vacuum hoses labeling them accordingly that they can be reattached later during reassembly. To remove the inlet and outlet fuel line nuts using a backup wrench removing those fuel line O-rings next are five TBI mounting bolts which lift that TBI unit up out of intake manifold where its old TBI manifold gasket will also be discarded. Put it onto a holding fixture if available or take care while working directly on benchtops without any additional protection against damages or spills when possible such as placing it directly upon top of another workbench. When cleaning up an individual part from dirtiness by inspection of mating surfaces as well as reinstallation of IAC valve or TPS do not forget to invert throttle body in order to remove IAC valve after taking off throttle body assembly including its old throttle body-to-fuel meter body gasket, the TPS or those screws attaching the fuel meter body to throttle body. Place fuel meter body assembly onto throttle body, secure it with thread locking compound on attaching screws and then install a new throttle body-to-fuel meter body gasket. Next the TBI unit with a new TBI-to-manifold gasket and new O-rings on fuel line nuts should be installed. As for vacuum hoses, throttle linkage, return spring(s), transmission control cable (automatics), cruise control cable and grommet with wire harness that returns through throttle body; after which all these parts can be reassembled back into place. Plug all electrical connectors in followed by connecting negative battery cable before checking to see if there is any fuel leaking with an engine off and ignition on. Set minimum idle speed in addition to TPS output values then reinstall air cleaner housing assembly adapter gaskets so as to finalize maintenance activities.
Posted by GMPartsGiant Specialist 
