GM 12574343
Fuel Rail

A proper replacement of the Fuel Rail assembly necessitates the procedure to vent fuel system pressure first. Disconnect both the fuel feed line quick connect fitting from the Fuel Rail as well as the evap purge tube from the throttle body control module and evap canister purge solenoid valve . First disconnect the engine wiring harness from the Fuel Injector harness electrical connectors after removing the Intake Manifold. You should clean the Fuel Rail assembly as well as the Cylinder Head with gm x-30a spray engine cleaner or equivalent while making sure the Fuel Rail remains dry from liquid solvents. The procedure requires removing Fuel Rail bolts and extracting the assembly while supporting the rail and avoiding contact to terms and spray tips of the injector electrical connectors. The holes need to be plugged up along with the fittings to keep outside materials from entering. Extract and dispose of the lower o-ring seals attached to the feed injectors. When the existing Fuel Rail will remain in place employ the installation procedures. The Fuel Rail disassembly process starts with harness clip removal from the Fuel Rail followed by removing the Fuel Rail harness and then taking out Fuel Injector retainers and fuel injectors. Upper o-ring seals follow for removal from the injectors. Before installation of new upper o-ring seals with mineral oil gm p/n 9981704 users should lightly lubricate them. Then position the fuel injectors with retainers alongside the harness which should get secured with clips. You should apply a small amount of mineral oil gm p/n 9981704 to the new lower o-ring seals before placing them at the injector tip ends. Set the Fuel Rail in position to the Cylinder Head where the injector spray tips should slide inside and push it until it reaches full seating. Before reinstalling parts the technician must first install Fuel Rail bolts at 10 n.m (89 lb in) then connect engine wiring harness to Fuel Injector harness electrical connector and put back Intake Manifold and attach evap purge tube to throttle body control module and evap canister purge solenoid valve . For fuel feed line quick connect fitting installation connect it to the Fuel Rail before conducting leakage inspections by following the sequence of turning on ignition with the engine off for two seconds and off for 10 seconds and on again with engine off to check for any fuel leaks.

Replacing the Fuel Rail assembly requires first draining the fuel system pressure from the components. You should disconnect both the fuel return hose/pipe and fuel feed hose/pipe from the Fuel Rail by using the quick connect fitting(s) service (Metal Collar) method. Download first the atmospheric vent hose from both the air cleaner resonator and the Fuel Pressure Regulator. You should remove the evaporative emission (EVAP) purge hose by disconnecting it between the throttle control module and the evap canister purge solenoid valve using quick connect fitting(s) service (Plastic Collar). To proceed with the repairs detach the intake manifold while disconnecting the Fuel Injector harness connector from the wiring harness electrical connector of the engine. Use a spray-type engine cleanser gm x-30a (or equivalent) to clean both the Fuel Rail assembly and cylinder head yet avoid putting Fuel Rail in liquid cleaning fluid. The technician should bolt out the Fuel Rail while maintaining careful removal to keep the injector electrical connector terminals and spray tips unharmed. Seal the fittings using caps along with plugging the holes to stop contamination. Cast away the lower o-ring seal of each Fuel Injector. Continue with the installation process when the Fuel Rail is excluded from replacement. The first step for disassembly involves removing the fuel injectors together with the Fuel Pressure Regulator and the Fuel Injector harness from the Fuel Rail. Begin assembly operations by attaching the Fuel Injector harness onto the Fuel Rail followed by positioning both the Fuel Pressure Regulator and fuel injectors. To install new lower Fuel Injector O-Ring seals you should apply little mineral oil gm p/n 9981704 before positioning them onto the spray tip ends of each Fuel Injector. Place the Fuel Rail next to the cylinder head so that its spray tip injector ends fit into position before tightening the Fuel Rail bolts to 10 n.m (89 lb in). Install the intake manifold by linking the Fuel Injector harness connector to the engine wiring harness electrical connector. After connecting the evap purge hose to both the throttle control module and the evap canister purge solenoid valve install the atmospheric vent hose to the air cleaner resonator and the Fuel Pressure Regulator. The installation ends with foil return hose/pipe attachment to Fuel Rail along with fuel feed hose/pipe connection followed by ignition leak check through on off ignition sessions of 2 and 10 seconds and engine off state inspection.

Relieve the fuel system pressure using Fuel Pressure Relief (With CH 48027) or (Without CH 48027).

Remove and discard the fuel injector lower O-ring seals from each injector.

Disconnect the fuel feed line quick connect fitting and the evaporative emission (EVAP) purge tube from the throttle body control module and the EVAP canister purge solenoid valve.