OEM 2004 GMC Envoy Fuel Rail

2004 GMC Envoy Fuel Rail Parts Questions & Experts Answers

• Q: How to replace the fuel rail assembly on 2004 GMC Envoy?

  A: The replacement of the Fuel Rail assembly requires the relief of fuel system pressure first. The Fuel Rail requires disconnection of both the fuel return hose/pipe by using the quick connect fitting(s) service (Metal Collar), and the fuel feed hose/pipe. Second, detach the atmospheric vent hose which operates between the air cleaner resonator and the Fuel Pressure Regulator. For inspection of the evaporative emission (EVAP) purge systempipe the installer will detach this tubing from the throttle control module and the evap canister purge solenoid valve using the quick connect fitting(s) service (Plastic Collar). Disconnect the Fuel Injector harness connector which exists between the engine wiring harness electrical connector and the Intake Manifold. Use gm x-30a engine cleaner or equivalent to spray the Fuel Rail assembly with Cylinder Head parts following the manufacturer instructions with caution when cleaning the Fuel Rail directly with solvent. Support the Fuel Rail as you uninstall the bolts and extract the rail from the Cylinder Head to avoid damaging terminal and spray tip components of the injector electrical connectors. Each Fuel Injector needs a replacement of its lower o-ring seal. The installation process should continue when the Fuel Rail will not be replaced. Separate the Fuel Rail components by taking out both fuel injectors, Fuel Pressure Regulator along with the Fuel Injector harness. Assemble the Fuel Rail by first placing the Fuel Injector harness followed by the Fuel Pressure Regulator then fuel injectors. A small amount of gm part number 9981704 mineral oil should lightly lubricate the new lower Fuel Injector o-ring seals which need to be placed on each Fuel Injector spray tip end. The Fuel Rail needs to be positioned on the Cylinder Head in a correct manner while the spray tip ends of the fuel injectors should be inserted before tightening the Fuel Rail bolts to 10 n.m (89 lb in). The installation continues with attaching the Fuel Injector harness connector to engine wiring harness electrical connector and installing the Intake Manifold. The honda certification evap purge hose requires attachment to the throttle control module and the evap canister purge solenoid valve through quick connect fitting(s) service (Plastic Collar) while the atmospheric vent hose connects to the air cleaner resonator and the Fuel Pressure Regulator. Use the quick connect fitting(s) service (Metal Collar) to join the fuel return hose/pipe with the fuel feed hose/pipe to the Fuel Rail. Afterward check for leaks by first enabling ignition while keeping the engine off for 2 seconds followed by a 10-second ignition disable period before restarting ignition with off engine and searching for fuel leaks.