GM 12579067
Fuel Rail

The first step to replace the Fuel Rail assembly requires draining pressure from the fuel system. A spray type engine cleaner with gm x-30a or equivalent should be used to clean the Fuel Rail assembly but only do as instructed on the package without putting it in liquid cleaning solvent. First detach pipes (2, 3) for fuel feed and return as well as the vacuum hose and air tube and PCV Valve leading from the cam cover. Disconnect the Fuel Injector electrical connectors from each Fuel Injector after removing the Fuel Rail bracket retainer nut then put the harness to the side. First remove the engine wiring harness from the Fuel Rail studs before proceeding to disconnect the Fuel Rail attaching studs then separate the Fuel Rail. Discard the injector lower 0-ring seals at each Fuel Injector spray tip end. The replacement of a Fuel Rail requires that you take away the fuel injectors and the Fuel Pressure Regulator. Before installing components put the Fuel Pressure Regulator in place first then follow by fuel injectors while applying engine oil to the new seals on each injector bottom. The assembly process includes Fuel Rail installation followed by Fuel Rail attaching stud tightening to 10 nm (89 lb in). After installing the Fuel Rail it will be the last process of the repair work. Connect Fuel Injector electrical connectors to each Fuel Injector before installing the Fuel Rail bracket retainer nut which needs to be tightened to 10 nm (89 lb in). The PCV Valve must be installed to the cam cover, coolant surge tank inlet pipe and pcv air tube. The connection of the Fuel Pressure Regulator vacuum hose and fuel feed and return pipes (2, 3) to the Fuel Rail must occur after reconnecting the negative Battery Cable and inspecting for fuel leaks will begin with the on ignition and engine off state for 2 seconds followed by 10 seconds of ignition off and then another 2 seconds of on ignition to examine for leaks. Install the Fuel Injector sight shield as the last step.

Service and repair operations on a Fuel Rail need the tools which include fuel pressure gauge (J34730-1A), Fuel Injector remover tool (J43013), and fuel line quick-connect separator tool set (J37088-A). Service starts with reducing fuel pressure then disconnection of iat sensor electrical connectors along with maf sensor connectors. Breakdown the air cleaner intake duct and perform cleaning on both Fuel Rail assembly and fuel pipe attaching components. The first step includes separating quick-connect fittings at the Fuel Rail together with completely removing the fuel pressure regulator vacuum hose as well as the pcv air tube. The procedure requires removal of the Fuel Rail end-point bracket retainer nut followed by the Fuel Injector electrical connector detachment. Afterward, place the harnesses to the side. The Fuel Injector remover tool (J43013) enables you to elevate the fuel injectors from their position on the Intake Manifold after detaching the Fuel Rail attaching bolts. Set the Fuel Rail assembly on a clean surface at a safe location that is cool and out of heat exposure. Elevate the Fuel Rail from above while disposing of the injector lower o-ring seals. Clean engine oil should be used to lubricate new lower injector o-ring seals before installing them to the spray tip end of each injector. Insert the Fuel Rail assembly onto the Intake Manifold until the fuel injectors seal completely before installing and tightening the attaching bolts to 10 n.m (89 lb in). Connect all Fuel Injector electrical connectors to their respective locations while installing the Fuel Rail end-point bracket retainer nut with torque at 10 n.m (89 lb in). After installation of the pcv air tube the technician should put back the fuel pressure regulator vacuum hose together with the quick-connect fittings and air cleaner intake duct and the iat and maf sensor connectors. To finish the procedure install the negative Battery Cable followed by a leak inspection with the ignition switch in on and off positions then tighten the fuel filler cap and reinstall the rear seat cushion and Intake Manifold sight shield and tighten its sight shield nuts to 3 n.m (27 lb in).

Remove the fuel injectors and the fuel pressure regulator.

Clean it with a spray type engine cleaner, GM X-30A or equivalent, following the package instructions without soaking it in liquid cleaning solvent.

Reinstall the PCV valve to the cam cover, the coolant surge tank inlet pipe, and the PCV air tube.

The fuel feed and return pipes, the fuel pressure regulator vacuum hose, the positive crankcase ventilation (PCV) air tube, and the PCV valve.

Relieve the fuel system pressure.

Reconnect the negative battery cable and inspect for fuel leaks.

Begin by relieving the fuel system pressure.

Disconnect the fuel feed and return pipes, the fuel pressure regulator vacuum hose, the positive crankcase ventilation (PCV) air tube, and the PCV valve from the cam cover.