Tools Required

J 38500-A: Fuel Injector Cleaner. See Special Tools and Equipment .
J 39021: Fuel Injector Coil/Balance Test. See Special Tools and Equipment .
J 39021-210: Injector Switch Box. See Special Tools and Equipment .
J 39021-301: Injector Harness Connector. See Special Tools and Equipment .
J 41413: EVAP Pressure/Purge Diagnostic Station. See Special Tools and Equipment .
J 44466-1: Fuel Recirculation Hose. See Special Tools and Equipment .
J 44466-10: Regulation and Hose Assembly. See Special Tools and Equipment .
J 44466-12 Fuel Metering Body Jumper Block. See Special Tools and Equipment .
J 44466-13 Screws. See Special Tools and Equipment .

Loosen the fuel filler cap to relieve vapor pressure in the fuel tank.
Remove the engine cover.
Remove the resonator and air inlet duct from throttle body.
Remove the brake booster vacuum hose and connector from intake manifold.
Remove the electrical connector from the central sequential fuel injection (CSFI) fuel metering body.
Remove the spark plug wires from 1, 3, and 5 from the distributor cap.
Relieve the fuel system pressure.
Disconnect fuel pipes (3) at rear of intake (1).

Fig 1: Locating Fuel Pipes
Courtesy of GENERAL MOTORS CORP.
Remove the fuel line bolt (4) at the rear of intake manifold.

Fig 2: Fuel Pipe & Components
Courtesy of GENERAL MOTORS CORP.
Remove the nuts (1) and clamp (2) from the fuel pipe.

Fig 3: Expanded View Of Fuel Pipe Clamp
Courtesy of GENERAL MOTORS CORP.
Remove fuel pipes from the metering body.
IMPORTANT: Make sure that the fuel pipe O-rings, washers and spacers are present and in their proper position.
Install the J 44466-12 (2) and the J 44466-13 (1) to the metering body and tighten.

Fig 4: Identifying J 44466-12 & J 44466-13
Courtesy of GENERAL MOTORS CORP.
Install the J 44466-1 (1) to the fuel pipe and tighten.

Fig 5: J 44466-1 Installed Onto Fuel Pipe
Courtesy of GENERAL MOTORS CORP.
Obtain the J 41413 , close the valve (2) on the tank (3) and remove the regulator assembly.

Fig 6: View Of Regulator and Hose Assembly
Courtesy of GENERAL MOTORS CORP.
Install the J 44466-10 (5) to the J 41413 tank (3).
Connect the J 44466-10 hose (1) to the J 44466-12 (3).

Fig 7: Locating J 44466-10 & J 44466-12
Courtesy of GENERAL MOTORS CORP.
Install the J 39021 , the J 39021-210 , and J 39021-301 (4) to the metering body electrical connector.
Adjust the amperage selector switch on the J 39021 to 0.5 amps.
Open the valve (2) on the tank (3).

Fig 8: View Of Regulator and Hose Assembly
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: The minimum pressure required on the gage (6) is 150 psi. If 150 psi is not obtained, the tank (3) must be refilled prior to performing this procedure.
Open the valve (4) on the J 44466-10 to pressurize the fuel system. Then close valve (4) before firing injectors.
Fire one injector using the J 39021 . Observe a pressure drop on the gage (6) and verify the injector/poppet valve operation. An injector/poppet that is "stuck" and not operational will have no pressure drop on the gage. If an injector remains "stuck", repeat the procedure multiple times, as required, until the injector is operational.
Repeat steps 19 and 20 for each individual injector to verify that all injector/poppet valve assemblies are unstuck and functional.
Shut off pressure valve (2) on the tank (3) of the J 41413 .
Bleed off the pressure at the J 44466-10 .

Fig 9: Locating J 44466-10 & J 44466-12

Courtesy of GENERAL MOTORS CORP.

Disconnect and remove the J 44466-10 (1) from the J 44466-12 (3) and the J 41413 .
Remove the J 39021-301 , J 39021-210 , and J 39021 from the metering body.
Install the vehicle electrical connector to the metering body.
Install brake booster vacuum hose and connector to the intake manifold.
Install ignition wires 1, 3, and 5 to the distributor cap.
Install the resonator and air intake duct to the throttle body and hand tighten wing nut.
IMPORTANT: Make sure the valve at the bottom of the canister (3) is closed.
Obtain J 38500-A (2).

Fig 10: Identifying Fuel Injector Cleaner
Courtesy of GENERAL MOTORS CORP.
Remove the canister top and add Top Engine Cleaner GM P/N 12346535 to the canister.
Fill the remainder of the canister with regular unleaded gasoline and install the canister top.
Suspend J 38500-A from a convenient location.
Connect the hose from J 38500-A (1) to the service port on the J 44466-12 (3).

Fig 11: Locating J 44466-10 & J 44466-12
Courtesy of GENERAL MOTORS CORP.
Open valve (3) at the bottom of J 38500-A .

Fig 12: Identifying Fuel Injector Cleaner
Courtesy of GENERAL MOTORS CORP.
Connect a shop air source to the fitting at the top of J 38500-A and adjust the regulator (1) to 75 psi.
Let the vehicle run at idle until the canister is empty and the vehicle stalls.
Remove the shop air supply from J 38500-A .
Depressurize the J 38500-A .
Disconnect the J 38500-A hose from the J 44466-12 .
Remove the resonator and air inlet duct from the throttle body and set aside.
Remove ignition wires 1, 3, and 5 from the distributor cap.
Remove brake booster vacuum hose and connector from the intake manifold.
Bleed the residual pressure from J 44466-12 .
Remove the J 44466-13 (1) and the J 44466-12 (2) from the metering body.

Fig 13: Identifying J 44466-12 & J 44466-13
Courtesy of GENERAL MOTORS CORP.

Fig 14: J 44466-1 Installed Onto Fuel Pipe

Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Make sure that all of the O-rings (6, 8), washers (7), and spacers (5) are present and in proper position.

Remove the J 44466-1 (1) from the fuel lines.
Install the fuel pipe (3) to the metering body.

Fig 15: Fuel Pipe & Components
Courtesy of GENERAL MOTORS CORP.

NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
Install the clamp (2) and nuts (1).
Tighten: Tighten nuts to 3 N.m (27 lb ft).
Apply threadlock GM P/N 12345382 or equivalent to the threads of the fuel pipe bolt (4).
Install the fuel pipe bolt.
Tighten: Tighten bolt to 6 N.m (53 lb ft).
Install the brake booster vacuum hose and connector to the intake manifold.
Install the resonator and air inlet duct to the throttle body.
Install brake booster vacuum hose and connector to the intake manifold.
Install ignition wires 1, 3, and 5 to the distributor cap.
Install engine cover.
IMPORTANT: Instruct the customer to add the remainder of the bottle of Port Fuel Injector Cleaner to the vehicle fuel tank at the next fill up.
Advise the customer to change brands of fuel.
Add one ounce of Port Fuel Injector Cleaner GN P/N 12345104 (in Canada P/N 12345515) to the vehicle fuel tank for each gallon of gasoline estimated to be in the tank.
Hand tighten the fuel tank filler cap.
Start the vehicle and check for fuel leaks.
Using a Tech II scan tool, check for any stored Powertrain DTC codes. Clear codes as required.
Disconnect Tech II scan tool.