GM 12559036
Injector

Three essential tools necessary for Fuel Injector maintenance and repair are fuel pressure gauge (J 34730-1A) together with Fuel Injector removal tool (J 43013) and fuel line quick-connect separator tool set (J 37088-A). Lowering the fuel pressure should be the first step to perform. First detach the Fuel Rail from the intake manifold followed by taking out the Fuel Injector assembly. The service starts with discarding the Fuel Injector upper o-ring and lower o-ring. Before applying the new o-rings to the Fuel Injector you must lubricate them with clean engine oil. Source the Fuel Injector to the Fuel Rail after which you should reconnect the Fuel Rail assembly. Reinstall the negative cable on the battery before tightening the fuel filler cap. An inspection for fuel leaks should begin by turning on the ignition for 2 seconds followed by keeping it off for 10 seconds before a second check of the fuel leakage. The last step requires installation of the intake manifold sight shield onto the engine and secure it with intake manifold sight shield nuts which must be tightened to 3 n.m (27 lb in) before putting back the rear seat cushion.

A repair or service of the Fuel Injector begins with removing the Fuel Rail then pushing the locking tab of the Fuel Rail toward its center until the injector detaches. First remove the upper o-ring and the lower o-ring sequences before discarding the injector o-ring seals. The correct placement of new o-rings is essential because blue and black o-rings differ in materials although both are the same size; blue o-rings should be in the upper position while black o-rings should be in the lower position to prevent fuel leaks and fires or personal injuries. The correct o-rings for fuel injectors must be replaced during maintenance while using parts with specified numbers. Clean engine oil must be used to lubricate new upper and lower o-rings before installing them on the Fuel Injector. Afterwards reinstall the Fuel Rail but first join the Fuel Injector to the Fuel Rail.

The required equipment for cleaning fuel injectors consists of fuel line shut-off adapters (J 37287), Fuel Injector cleaner (J 38500-A) and three adapters of different sizes (J 42873-1, J 42873-2, J 42964-1 and J 42964-2). The cleaning operation requires gm top-engine cleaner, U.S. P/N 12346535 or canadian P/N 992872. Add solution only to j 38500-a at a maximum concentration of 10 percent. The cleaning procedure for j 38500-a requires two solution tanks to reach the total amount of 960 ml (32.4 oz) cleaning solution. Prepare for the operation by disabling the vehicle Fuel Pump before disconnecting the fuel lines and plugging them with the proper adapters. Connect the j 38500-a to the Fuel Rail before pressurizing it to 510 kpa (75 psi) while running the engine unit it stalls. The vehicle needs to operate for another 2 minutes following the removal of the j 38500-a then returning all fuel lines to their original position. Test all injectors for balance using the proper equipment while replacing the injector that drops its pressure by more than 15 kpa (2 psi). Also add port Fuel Injector cleaner gm P/N 12345104 (Canadian P/N 10953467) at the rate of one ounce per gallon of gasoline to the fuel tank and provide gm port Fuel Injector cleaner maintenance recommendations to the customer. Drive the vehicle to test that the issue has been correctly addressed.

Always use the correct part number.

Lubricate the new upper and lower O-rings with clean engine oil.

Take off the upper O-ring and lower O-ring, discarding the old injector O-ring seals.

Reinstall the fuel injector onto the fuel rail and then secure the fuel rail back in place.

Take out the upper O-ring and lower O-ring from the fuel injector, discarding the old seals.

Lubricate the new upper and lower O-rings with clean engine oil.

Whenever servicing the injectors to avoid vacuum leaks and driveability issues.

Take off the upper O-ring and lower O-ring, discarding the injector O-ring seals.

To prevent vacuum leaks and driveability issues.

Reconnect the fuel injector electrical connector.