GM Service Manual Online
For 1990-2009 cars only

Excessive Exhaust Odors Symptom

Step

Action

Value(s)

Yes

No

DEFINITION: Vehicle has excessive rotten egg smell. Excessive odors do not necessarily indicate excessive emissions.

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Perform a bulletin search.
  2. If a bulletin that addresses the symptom is found, correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

--

Go to Step 18

Go to Step 3

3

Was a thorough visual/physical check performed?

--

Go to Step 4

Go to Symptoms

4

  1. Check the following locations for vacuum leaks:
  2. • The vacuum lines
    • The EGR system
    • The intake manifold
    • The throttle body
  3. If a problem is found, repair as necessary.

Were any vacuum leaks located?

--

Go to Step 18

Go to Step 5

5

  1. Check the fuel cap for proper installation.
  2. Secure the fuel cap if necessary.

Was the fuel cap installed properly?

--

Go to Step 6

Go to Step 18

6

  1. Check the fuel pressure. Perform Fuel System Pressure Test (VIN K) .
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 7

7

  1. Check for faulty, plugged, or incorrectly installed crankcase ventilation valve. Also check the crankcase ventilation system for restrictions.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 8

8

  1. Check the injector connections.
  2. If any of the injector connectors are connected to an incorrect cylinder, correct as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 9

9

  1. Perform the Injector Flow/Voltage Drop Check. Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) or to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F) .
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 10

10

  1. Refer to Diagnostic Starting Point in Engine Cooling for cooling system diagnosis.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 11

11

  1. Check the EVAP canister for fuel loading. Refer to Evaporative Emission Control System Diagnosis .
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 12

12

Remove any excessive carbon buildup with Top engine cleaner. Review the instructions on the Top engine cleaner can.

Is the exhaust odor still present?

--

Go to Step 13

Go to Step 18

13

Check the items that can cause the engine to run rich. Make any necessary repairs.

Is the exhaust odor still present?

--

Go to Step 14

Go to Step 18

14

Check the items that can cause the engine to run lean. Make any necessary repairs.

Is the exhaust odor still present?

--

Go to Step 15

Go to Step 18

15

  1. Check the EGR system. Refer to Exhaust Gas Recirculation (EGR) System Description .
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 16

16

  1. Check for an engine mechanical problem. Perform a cylinder compression check. Refer to Engine Compression Test in Engine Mechanical.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Step 17

17

  1. Review all diagnostic procedures within this table.
  2. If all procedures have been completed and no malfunctions have been found, review/inspect the following:
  3. •  Visual/physical inspection
    • The scan tool data
    • The Freeze Frame and Failure Records data
    •  All electrical connections within a suspected circuit and/or system
  4. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 18

Go to Powertrain On Board Diagnostic (OBD) System Check

18

Operate the vehicle to duplicate conditions present when the original symptom was noted.

Is the symptom still present?

--

Go to Step 3

System OK