Hummer H2. Manual - part 70

INITIAL START-UP 

Start engine and operate engine at low speed while checking for coolant, fuel and oil leaks. Stop engine. 
Recheck coolant and oil level. Adjust if necessary.  

CAMSHAFT 

Break-in procedure is required when new or reground camshaft has been installed. Operate and maintain engine 
speed between 1500-2500 RPM for approximately 30 minutes. Procedure may vary due to manufacturer's 
recommendations.  

PISTON RINGS 

Piston rings require a break-in procedure to ensure seating of rings to cylinder walls. Serious damage may occur 
to rings if correct procedures are not followed.  

Extremely high piston ring temperatures are obtained during break-in process. If rings are exposed to 
excessively high RPM or high cylinder pressures, ring damage can occur. Follow piston ring manufacturer's 
recommended break-in procedure.  

FINAL ADJUSTMENTS 

Check or adjust ignition timing and dwell (if applicable). Adjust valves (if necessary). Adjust idle speed and 
mixture. Retighten cylinder heads (if required). If cylinder head or block is aluminum, retighten bolts when 
engine is cold. Follow the engine manufacturer's recommended break-in procedure and maintenance schedule 
for new engines.  

crankcase conditioner be added to engine oil. The engine should be operated 
for specified amount of time to aid in lifter break-in procedure. 

NOTE:

Some manufacturers require that head bolts be retightened after specified 
amount of operation. This must be done to prevent head gasket failure. 

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Overhaul Procedures

  

GENERAL INFORMATION 

Engine Performance Diagnostic Routine Outline 

WHERE DOES DRIVEABILITY DIAGNOSIS START? 

PERFORM BASIC INSPECTION 

1. Verify Customer Complaint  

2. Perform Visual Inspection (See Basic Diagnostic Procedures)  

3. Test Engine Sub-Systems (See Basic Diagnostic Procedures) 

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Mechanical Condition (Compression)  

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Ignition Output  

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Fuel Delivery  

4. Check Air Induction System For Leaks  

5. Check & Adjust Basic Engine Settings (See On-Vehicle Adjustments) 

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Ignition Timing  

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Idle Speed  

CHECK FOR TROUBLE CODES 

1. Check for Diagnostic Trouble Codes (DTCs). (See Self-Diagnostics)  

2. Repair cause of DTCs.  

3. Clear PCM memory and repeat self-test.  

DIAGNOSE SYMPTOM 

1. If no self-diagnostics available, or no trouble codes present, identify symptom.  

2. See trouble shooting procedure to identify problem. (See Trouble Shooting - No Codes)  

TEST SYSTEM 

1. Perform required tests. (See Systems & Component Testing)  

2. Verify complaint is repaired.  

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Performance Diagnostic Routine Outline

  

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Performance Diagnostic Routine Outline

  

GENERAL INFORMATION 

Engine Performance Safety Precautions 

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Always refer to Emission Decal in engine compartment before servicing vehicle. If manual and decal 
differ, always use decal specifications.  

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Do not allow or create a condition of misfire in more than one cylinder for an extended period of time. 
Damage to converter may occur due to loading converter with unburned air/fuel mixture.  

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Always turn ignition off and disconnect negative battery cable BEFORE disconnecting or connecting 
computer or other electrical components.  

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DO NOT drop or shock electrical components such as computer, airflow meter, etc.  

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DO NOT use fuel system cleaning compounds that are not recommended by the manufacturer. Damage to 
gaskets, diaphragm materials and catalytic converter may result.  

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Before performing a compression test or cranking engine using a remote starter switch, disconnect coil 
wire from distributor and secure it to a good engine ground, or disable ignition.  

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Before disconnecting any fuel system component, ensure fuel system pressure is released.  

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Use a shop towel to absorb any spilled fuel to prevent fire.  

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DO NOT create sparks or have an open flame near battery.  

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If any fuel system components such as hoses or clamps are replaced, ensure they are replaced with 
components designed for fuel system use.  

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Always reassemble throttle body components with new gaskets, "O" rings and seals.  

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If equipped with an inertia switch, DO NOT reset switch until fuel system has been inspected for leaks.  

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Wear safety goggles when drilling or grinding.  

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Wear proper clothing which protects against chemicals and other hazards. 

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Performance Safety Precautions

  

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Performance Safety Precautions

  

GENERAL INFORMATION 

TROUBLE SHOOTING 

ENGINE PERFORMANCE 

TUNE-UP TROUBLE SHOOTING 

Problem & Possible Cause 

Action 

Carbon Fouled Plugs 

Clogged Air Filter 

Replace Air Filter 

Incorrect Idle Speed 

Reset Idle Speed 

Faulty Ignition Wiring 

Replace Ignition Wiring 

Sticky Valves/Worn Valve Seal 

Check Valve Train 

Fuel Injection Operation 

Check Fuel Injection 

Wet/Oil Fouled Plugs 

Worn Rings/Pistons 

Overhaul/Replace Engine 

Excessive Cylinder Wear 

Overhaul/Replace Engine 

Plug Gap Bridged 

Combustion Chamber Carbon Deposits 

Clean Combustion Chamber 

Blistered Electrode 

Engine Overheating 

Check Cooling System 

Loose Spark Plugs 

Clean/Torque Plugs 

Over-Advanced Timing 

Reset Timing 

Wrong Plug Heat Range 

Install Correct Plug 

Melted Electrodes 

Incorrect Timing 

Reset Timing 

Burned Valves 

Replace Valves 

Engine Overheating 

Check Cooling System 

Wrong Plug Heat Range 

Install Correct Plug 

Engine Won't Start 

Loose Connections 

Check Connections 

No Power 

Check Fuses/Battery 

Loose/Worn Timing Belt/Chain/Gears 

Check Belt/Chain/Gears 

Engine Runs Rough 

Leaky/Clogged Fuel Injectors 

Repair Fuel Injectors 

Leaky/Clogged Fuel Lines 

Repair Fuel Lines 

Clogged Fuel Filter 

Replace Fuel Filter 

Incorrect Timing 

Reset Timing/Check Advance 

Faulty Plugs/Wires 

Replace Plugs/Wires 

Uneven Compression 

Overhaul/Replace Engine 

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION TROUBLE SHOOTING

  

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION TROUBLE SHOOTING