Hummer H3. Manual — part 1156

J 42000

Battery Tester

J 45681

Jumper Harness

2007 Hummer H3

2007 ENGINE Engine Electrical - H3

2007 ENGINE

Engine Exhaust - H3

SPECIFICATIONS

FASTENER TIGHTENING SPECIFICATIONS

Fastener Tightening Specifications

DIAGNOSTIC INFORMATION AND PROCEDURES

DIAGNOSTIC STARTING POINT - ENGINE EXHAUST

Begin the system diagnosis by reviewing the system Description and Operation. Reviewing the
information will help you determine the correct symptom diagnostic procedure when a
malfunction exists. It will also help you determine if the condition described by the customer is
normal operation. Refer to Symptoms - Engine Exhaust in order to identify the correct
procedure for diagnosing the system.

SYMPTOMS - ENGINE EXHAUST

Review the Exhaust System Description and Operation in order to familiarize yourself with

Application

Specification

Metric

English

Catalytic Converter Heat Shield

9 N.m

80 lb in

Catalytic Converter Nut

50 N.m

37 lb ft

Exhaust Manifold Bolt

First Pass

20 N.m

15 lb ft

Second Pass

20 N.m

15 lb ft

Final Pass

20 N.m

15 lb ft

Exhaust Manifold Heat Shield Nut

10 N.m

89 lb in

Exhaust Muffler Heat Shield

9 N.m

80 lb in

Exhaust Pipe Heat Shield

9 N.m

80 lb in

Leaf Spring Bolt and Nut

85 N.m

63 lb ft

Lower Shock Absorber Bolt and Nut

95 N.m

70 lb ft

Muffler Nut

45 N.m

33 lb ft

Transmission Filler Tube Bracket Nut

12.5 N.m

111 lb in

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3

the system functions. Refer to Exhaust System Description.

All diagnostics on a vehicle should follow a logical process. Strategy Based Diagnostics is a
uniform approach for repairing all systems. The diagnostic flow is the place to start when
repairs are necessary and may always be used in order to resolve a system problem. For a
detailed explanation, refer to Strategy Based Diagnosis .

Visual/Physical Inspection

Inspect for aftermarket or non-OEM devices such as, but not including; tailpipe extensions,
headers and exhaust cutouts. This could affect the operation and proper performance of the
exhaust system.

Verify the exact operating conditions under which the concern exists. Note factors such as
engine RPM, engine temperature, engine load and frequency of concern.

Inspect the easily accessible or visible system components for obvious damage or conditions
which could cause any symptom.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system
is operating as designed.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:

Loss of power - Refer to Restricted Exhaust.

Poor acceleration - Refer to Restricted Exhaust.

Poor fuel economy - Refer to Restricted Exhaust.

Excessive smoke - diesel - Refer to Restricted Exhaust.

Exhaust hissing noise - Refer to Exhaust Leakage.

Exhaust popping noise - Refer to Exhaust Leakage.

Exhaust rattle noise - Refer to Exhaust Noise.

Loud exhaust noise - Refer to Exhaust Noise

Exhaust buzz, groan, hum noise - Refer to Exhaust Noise.

RESTRICTED EXHAUST

Tools Required

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3

J 35314-A Exhaust Back Pressure Gage. See Special Tools.

Diagnostic Aids

For dual exhaust systems a quick check of exhaust flow will help determine which side of the
exhaust system is restricted. The side that has less exhaust flow is the side that will be suspect and
diagnosis should begin there.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4: The exhaust system has very low back pressure under normal conditions. If the exhaust
system is restricted, a significant increase in the exhaust pressure is noticed on the J 35314-
A . See Special Tools. Removing the heated oxygen sensor (HO2S) may set a DTC. When
finishing this diagnostic table, be sure to clear all codes.

5: This step will isolate the catalytic converter from the remainder of the exhaust system.

8: Confirming that the condition has been fixed is essential. If the symptom still exists and
the vehicle has a dual exhaust system, proceed to step 2 and repeat diagnostic procedure on
the opposite exhaust pipe.

Restricted Exhaust

CAUTION: Refer to Hot Exhaust System Caution .

Step

Action

Value(s)

Yes

No

1

Did you verify the customers
complaint?

-

Go to Step 2

-

2

Did you review the exhaust
symptoms diagnostic information
and perform the necessary
inspections?

-

Go to Step 3

Go to
Symptoms -
Engine
Exhaust

3

Is the system equipped with dual
exhaust?

-

Go to
Diagnostic
Aids.

Go to Step 4

1. Remove the heated oxygen

sensor (HO2S) that is in front
of the catalytic converter.
Refer to Heated Oxygen

2007 Hummer H3

2007 ENGINE Engine Exhaust - H3