GM 91173903
Injector

Beginning Fuel Injector service requires users to both relieve fuel pressure then disconnect the negative Battery Cable. Detach the PCV Valve and hose from the intake and valve cover area after taking out all 3 bolts and the Intake Manifold brace from the engine's interior. The electrical connectors need detachment from the 4 fuel injectors along with the removal of the vacuum hose from the fuel-pressure regulator. The service requires removal of the fuel feed hose from the Fuel Rail inlet pipe while simultaneously removing the fuel return hose from the Fuel Rail return pipe. Proceed by first removing the two Fuel Rail bolts then taking off the Fuel Rail from the Intake Manifold. Afterward remove the four fuel injectors from the rail. The installation process requires brand new o-rings and grommets on every Fuel Injector followed by light fuel application on the o-rings before placing them in position. The inspection of Fuel Injector cushions should be performed to identify any signs of damage so proper replacements can be made. Position the Fuel Rail alongside 4 fuel injectors using cushions onto the Intake Manifold after securing it with 2 bolts while tightening them to 18-28 n.m (13-20 lb ft). Swipe the fuel injectors for smooth movement before installing the fuel feed hose to the inlet pipe and securing it with clamps followed by connecting the return hose to the outlet pipe. Reinstall the vacuum hose to its fuel-pressure regulator position and reestablish electrical connector connection with fuel injectors. After connecting the Intake Manifold brace to its position with 3 bolts which require 25-35 n.m (18.5-25 lb ft) torque then add the PCV Valve and hose into their respective positions on the intake plenum and valve cover. To complete the procedure return the negative Battery Cable and tighten its terminal retainer to 5.5 n.m (49 lb in). Then turn on the ignition to activate the fuel system and turn it off to inspect for leaks before repairing any damages.