GM 17120039
Fuel Rail

Service and repair of the Fuel Rail requires the fuel pressure gauge tool with its part number j 34730-1a. Start the process by unhooking the negative Battery Cable before you eliminate pressure from the fuel system. The upper Intake Manifold needs removal before cleaning the Fuel Rail assembly with gm x-30a or equivalent engine cleaner according to the package instructions while avoiding prolonged Fuel Rail immersion in liquid solvent. Users must first detach fuel pipes from their rail position while removing the engine fuel pipe bracket bolt before disconnecting electrical injectors with pliers and taking out Fuel Rail keeping bolts. The second step involves removing the Fuel Rail from the Intake Manifold after you disconnect the vacuum hose line which leads to the pressure regulator. Follow the specified package methods using x-30a product to clean the fuel feed and return pipe o-rings before removing the injector o-ring seals from the spray tip end of each injector. Keep the o-ring back ups for future use. Before mounting new o-rings on each injector you need to put the o-ring back ups onto injectors and then apply engine oil to the o-rings but place them on the spray tips. After tilting the Fuel Rail assembly inside the Intake Manifold, install each injector and secure Fuel Rail attaching bolts with torque to 10 n.m (89 lb in). As a part of installation you should first attach injector electrical connectors before you put on new o-rings to the fuel pipes and then connect feed and return pipes by using a back up wrench to prevent turning motion and tightening the fittings to 27 n.m. The service technician should reengage the negative Battery Cable after reinstalling the fuel filler cap and delay a leak check with an on-off-on ignition switch procedure before checking for fuel leakage. To finish the installation process install the upper Intake Manifold as the last step.

The first step when replacing the Fuel Rail assembly is to locate its eight-digit identification number which will help with part replacements and servicing. The repair starts by removing the negative Battery Cable then taking out the engine sight shield. Use gm x-30a spray-type engine cleaner according to package directions to clean the fuel rails while preventing their immersion in liquid cleaning agents. The procedure starts by detaching the avalanche control cables from their anchors on the cable bracket and throttle body then eradicating the engine sight shield bracket bolts and bracket. Disengage the upper engine wire harness retainer nut then disconnect the evaporative emission (EVAP) purge solenoid electrical connector before sitting the upper engine wire harness to the side. The first step should be to release fuel system pressure followed by connecting the appropriate injectors to their proper connectors to keep the injector firing sequence correct upon reassembly. Follow steps to disconnect the injector connector where you should pull the top portion until it reaches the white marker then push the near the lower end to unhinge each connector. The procedure begins by disconnecting pipes from the Fuel Rail as well as the vacuum line that leads to the fuel pressure regulator. The crossover tube to right Fuel Rail retainer screw should be loosened while the Fuel Rail attachment bolts need removal before extracting the Fuel Rail assembly. Discard and remove the injector lower o-ring seals that exist at the spray tip end of all injectors. Engine oil must lubricate the fresh lower o-ring seals before placing them on injector spray tips for installation. Install a new lubricated o-ring in the crossover tube before placing it into the right Fuel Rail retainer socket. The crossover tube should be installed into the right Fuel Rail before attaching it loosely to the right fuel retainer. Attach the Fuel Rail assembly to the Intake Manifold, applying a 5 mm band of gm p/n 12345382 thread lock to the threads of the Fuel Rail bolts, and then install and tighten the Fuel Rail attaching bolts to 10 n.m and the right crossover pipe retainer screw to 3.8 n.m. Connect the fuel pressure regulator vacuum line, the fuel feed and return pipes to the Fuel Rail, and the injector electrical connectors in the correct order, rotating the injectors as necessary to avoid stretching the wire harness. Position the upper engine wire harness, connect the evap purge solenoid connector, and install the retainer nut to the upper engine wire harness, tightening it to 5.5 n.m. Reconnect the accelerator control cable and cruise control cable to the cable bracket and throttle body, then install the engine sight shield mounting bracket and bolts, tightening them to 10 n.m. Tighten the fuel filler cap, reconnect the negative Battery Cable, and inspect for leaks by turning the ignition on for 2 seconds, off for 10 seconds, and then on again, checking for fuel leaks. Attach the engine sight shield and secure its bolts at 10 n.m torque.