GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Catera 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 Excessive Exhaust Emissions or Odors

Checks

Action

DEFINITION: The vehicles has an excessive rotten egg smell. Excessive odors do not necessarily indicate excessive emissions.

Preliminary
    • Refer to Important Preliminary Checks Before Starting in Symptoms .
    • Search for bulletins.
    • Inspect the ECM grounds for being clean, tight, and in the proper locations. Refer to Engine Controls Schematics .
    • Remove the air filter element and inspect for dirt or for being restricted. Refer to Air Filter Element and Air Cleaner Assembly . Replace as necessary.

Fuel System
    • Inspect the type, quality and alcohol content of the fuel. Refer to Fuel Specifications and Alcohol/Contaminants-in-Fuel Diagnosis .
    • Test the fuel injectors. Refer to Fuel Injector Solenoid Coil Test .
    • Test for incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Test for a restricted fuel filter. Refer to Fuel System Diagnosis .
    • Inspect for foreign material accumulation in the throttle bore, coking on the throttle valve, or on the throttle shaft. Refer to Throttle Body Cleaning . Also inspect for throttle body tampering.
    • Inspect for items which can cause an engine to run rich (long term fuel trim near -13 percent). For a rich condition, refer to DTC P0172 Fuel Trim System Rich Bank 1 and DTC P0175 Fuel Trim System Rich Bank 2 .

Sensor/System
    • Inspect the air intake system and the crankcase for air leaks.
    • Test the crankcase ventilation system for proper operation. Refer to Crankcase Ventilation System Diagnosis .

Ignition System
    • Test for proper ignition voltage output with a J 26792 spark tester. Refer to Ignition System Check .
    • Test for secondary ignition system leakage. Perform the procedure in the Diagnostic Aids portion of the Ignition System Check .
    • Remove the spark plugs and inspect for the following conditions:
       - Correct heat range
       - Wet plugs
       - Cracks
       - Wear
       - Improper gap
       - Burned electrodes
       - Heavy deposits
    • An improper spark plug gap may cause a driveability concern. Gap the spark plugs using a wire gauge gap tool. Refer to Spark Plug Replacement in Engine Electrical.
    • Determine the cause of the fouling before replacing the spark plugs if spark plugs are gas, coolant or oil fouled. Refer to Spark Plug Visual Diagnosis in Engine Electrical.
       - For diagnosis of a rich condition, refer to DTC P0172 Fuel Trim System Rich Bank 1 or to DTC P0175 Fuel Trim System Rich Bank 2 .
       - For diagnosis of coolant contaminated spark plugs, refer to Loss of Coolant in Engine Cooling.
       - For diagnosis of oil fouled spark plugs, refer to Oil Consumption Diagnosis in Engine Mechanical.

Engine Cooling System
    • Inspect the engine coolant level for being low. Refer to Cooling System Draining and Filling in Engine Cooling.
    • Test the engine thermostat for proper operation and correct heat range. Refer to Thermostat Diagnosis in Engine Cooling.

Engine Mechanical
    • Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • Check for incorrect camshaft timing. Refer to Timing Belt Timing Adjustment in Engine Mechanical.
    • For incorrect basic engine parts, inspect the following:
       - Camshafts, refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.
       - Cylinder heads, refer to Cylinder Head Cleaning and Inspection in Engine Mechanical.
       - Pistons, connecting rods or bearings, refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical.

Additional Checks
    • Visually/physically inspect the vacuum hoses for splits, kinks, and proper connections and routing as shown on vehicle emission control information label or in Emission Hose Routing Diagram .
    • Inspect for air leaks in the following areas:
       - The throttle body mounting area
       - The mass air flow (MAF) sensor
       - The duct between the MAF and the throttle body
    • Inspect the exhaust system components for possible restrictions:
       - The exhaust system for physical damage
       - The mufflers for heat distress or possible internal failure
       - The catalytic converters for possible plugged pipes by comparing the exhaust system back pressure on each side of engine. Refer to Restricted Exhaust System Check .