Hummer H2. Manual - part 1442

Fig. 59: MAF/IAT Sensor & Air Cleaner Assembly
Courtesy of GENERAL MOTORS CORP. 

6. Install the air intake duct. Refer to Air Cleaner Resonator Outlet Duct Replacement .  

7. Connect the intake air temperature sensor harness connector.  

8. Refill the cooling system. Refer to Draining and Filling Cooling System in Engine Cooling.  

9. Verify that the vehicle meets the following conditions: 

z

The vehicle is not in a Reduced Engine Power mode.  

z

The ignition is ON.  

z

The engine is OFF.  

10. Connect a scan tool in order to test for a proper throttle-opening and throttle-closing range.  

11. Operate the accelerator pedal and monitor the throttle angles. The accelerator pedal should operate freely, 

without binding, between a closed throttle, and a wide open throttle (WOT).  

12. Start the engine.  

13. Inspect for coolant leaks.  

FUEL PRESSURE RELIEF PROCEDURE 

Tools Required 

J 34730-1A Fuel Pressure Gauge. See Special Tools and Equipment . 

CAUTION: Relieve the fuel system pressure before servicing fuel system components 

in order to reduce the risk of fire and personal injury. 
After relieving the system pressure, a small amount of fuel may be 
released when servicing the fuel lines or connections. In order to reduce 
the chance of personal injury, cover the regulator and the fuel line fittings 
with a shop towel before disconnecting. This will catch any fuel that may 
leak out. Place the towel in an approved container when the disconnection 
is complete.

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls (Introduction) - 4.8L, 5.3L, and 6.0L - Hummer H2

  

Fig. 60: Identifying Fuel Pressure Gauge J 34730-1A 
Courtesy of GENERAL MOTORS CORP. 

1. Disconnect the negative battery cable in order to avoid possible fuel discharge if an accidental attempt is 

made to start the engine. Refer to Battery Negative Cable Disconnect/Connect Procedure (Single 
Battery) in Engine Electrical.  

2. Remove the engine sight shield. Refer to Engine Sight Shield Replacement (6.0L (LQ4)) in Engine 

Mechanical.  

3. Loosen the fuel filler cap in order to relieve the fuel tank vapor pressure. 

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls (Introduction) - 4.8L, 5.3L, and 6.0L - Hummer H2

  

4. Connect the J 34730-1A to the fuel pressure valve. Wrap a shop towel around the fitting while 

connecting the gauge in order to avoid spillage. See Special Tools and Equipment .  

5. Install the bleed hose of the gauge into an approved container.  

6. Open the valve on the gauge to bleed the system pressure. The fuel connections are now safe for 

servicing.  

7. Drain any fuel remaining in the gauge into an approved container.  

FUEL PRESSURE GAUGE INSTALLATION AND REMOVAL 

Installation Procedure 

CAUTION: Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices.

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls (Introduction) - 4.8L, 5.3L, and 6.0L - Hummer H2

  

Fig. 61: Identifying Fuel Pressure Gauge J 34730-1A 
Courtesy of GENERAL MOTORS CORP. 

CAUTION: Refer to Fuel Gauge Leak Caution in Cautions and Notices.

NOTE:

Clean all of the following areas before performing any disconnections in 
order to avoid possible contamination in the system: 

 

2004 Hummer H2 

2004 ENGINE PERFORMANCE Engine Controls (Introduction) - 4.8L, 5.3L, and 6.0L - Hummer H2