OEM GMC Sierra 3500 Classic Fuel Injector

GMC Sierra 3500 Classic Fuel Injector Parts Questions & Experts Answers

• Injector
  12580426
  Q: How to replace the fuel injectors on GMC Sierra 3500 Classic?

  A: First prepare your work by removing the air cleaner outlet duct followed by draining fuel system pressure with ch 48027. You need to start by taking off the engine wiring harness bracket nut followed by removing electrical connectors from the evap purge solenoid , generator , MAP Sensor , ignition coil main electrical connector , and the fuel injectors (3 and 7). When disconnecting these connectors you should mark them for correct reassembly. Start by removing the negative battery cable stud together with terminal from the right Cylinder Head followed by disassembly of the engine wiring harness clips and positive crankcase ventilation (PCV) hose. Begin by detaching the Fuel Rail bolts followed by removing the retainer that shields the evap canister purge solenoid to the Fuel Rail and disconnecting both the chassis fuel feed pipe and evap tube quick connect fittings. Withdraw the Fuel Rail assembly after checking that the electrical connections are undamaged while throwing away the existing o-ring seals which damped the fuel injectors at positions 2 and 4. Clean engine oil should be used to lubricate new o-ring seals before placing them on the injectors which will then be installed into the Fuel Rail under retainers . Set the Fuel Rail in position onto the Intake Manifold with force until it achieves complete seating and then install and tighten the Fuel Rail bolts to 10 n.m (89 lb in). The service technician should install evap tube and purge solenoid and chassis fuel feed pipe and pcv hose connections in sequence. After properly positioning the engine wiring harness install its clips before connecting the negative battery cable terminal and stud by tightening the stud to 25 n.m (18 lb ft). Secure the electrical connectors to the ignition coil along with electronic throttle control along with fuel injectors while confirming that cpa retainers are properly placed. The last installation step involves securing the engine wiring harness bracket nut to 5 n.m (44 lb in) while also performing the specified turnover of the ignition and leak checks before reinstalling the air cleaner outlet duct.