8 - Fuel Injector Tip Leakage Test

TOOLS REQUIRED:  SA9127E Gauge Bar Set

1. Remove air induction tube and resonator.
2. Relieve fuel system pressure. Refer to RELIEVING FUEL PRESSURE .
   Fig 1: Relieving Fuel System Pressure

   Courtesy of GENERAL MOTORS CORP.
3. Remove throttle cable from throttle cable support bracket.
4. Remove upper power steering support brace.
5. Connect Gauge Bar Set SA9127E to fuel pressure port.
   CAUTION: LAY SHOP TOWELS ON INTAKE MANIFOLD AND CAM COVER TO COLLECT ANY FUEL.
   CAUTION: MAKE SURE THE INJECTORS ARE POSITIONED TO PREVENT FUEL FROM BEING SPRAYED ONTO THE ENGINE. MAKE SURE THAT THE INJECTOR RETAINING CLIPS ARE PROPERLY INSTALLED.
6. Remove fuel feed line clip attachment nut (10 mm hex).
7. Remove fuel rail assembly attachment bolts and pull fuel rail back far enough so that the nozzles of the fuel injectors are visible but still in ports. Attach the fuel rail to the intake manifold with safety wire.
   Fig 2: Removing Fuel Rail Assembly

   Courtesy of GENERAL MOTORS CORP.
8. Connect fuel pressure gauge bar to pressure adapter.
9. Wipe the tips of the fuel injectors free of any fuel or debris and place a clean white towel directly under fuel injectors. The clean white towel must lightly contact each fuel injector tip. This will serve as an indicator of leaky fuel injectors by showing spots where fuel has leaked as well as block the injector ports from any debris that might enter.
10. Connect Scan tool and turn ignition ON. Refer to ENERGIZING THE FUEL PUMP .
    NOTE: Battery must be at a minimum of 12 volts when performing any fuel system test. Charge battery before proceeding if below 12 volts.
11. Energize fuel pump using Scan tool and observe the fuel injector tips for leakage of fuel. If one or more of the white towels becomes wet with fuel after five minutes, replace the faulty fuel injector. It is very difficult to measure drops of fuel from a injector. Refer to "FUEL INJECTOR ASSEMBLY (SOHC)  or FUEL INJECTOR ASSEMBLY (DOHC)  .
    NOTE: Pressure gage reading should be approximately 276-379 kPa (40-55 psi).
12. Test assembly a minimum of two times.
13. Install bleed hose from pressure test adapter (309725) into an approved container and open valve to bleed system pressure. Once pressure is bled, remove fuel gage adapter from the fuel pressure test port and recap it.
    Fig 3: Install Bleed Hose From Pressure Test Adapter

    Courtesy of GENERAL MOTORS CORP.
14. Lubricate injector O-rings with clean engine oil and install fuel rail assembly. Refer to FUEL RAIL ASSEMBLY (DOHC)  or FUEL RAIL ASSEMBLY (SOHC)  .
15. Start engine and check for leaks.