Excessive Exhaust Emissions (Odors)

Definition: Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odors do not necessarily indicate excessive emissions.

PRELIMINARY CHECKS
^ Refer to Important Preliminary Checks. Testing and Inspection
^ Perform Diagnostic System Check Testing and Inspection
^ Make sure engine is at normal operating temperature.
^ If EMISSION TEST shows excessive CO and HC check items which cause vehicle to run RICH. Long term fuel trim memory less than 115 refer to Diagnostic Charts/Trouble Code Charts/Code 45 Oxygen Sensor (Rich Exhaust Indication) - Diagnostic Aids. Powertrain Controls - ECM/PCM
^ If EMISSION TEST shows excessive NOx check items which cause engine to operate LEAN or too hot.
^ Service Bulletins for updates.

SENSORS
CHECK: If the scan tool indicates a very high coolant temperature and the system is running LEAN: check the cooling system and cooling fan for proper operation.

FUEL SYSTEM
CHECK: If the system is running rich, (long term fuel trim less than 115), refer to Diagnostic Charts/Trouble Code Charts/Code 45 Oxygen Sensor (Rich Exhaust Indication) - Diagnostic Aids. Powertrain Controls - ECM/PCM
OR
If the system is running lean, (long term fuel trim greater than 150), refer to Diagnostic Charts/Trouble Code Charts/Code 44 Oxygen Sensor (Lean Exhaust Indication) - Diagnostic Aids. Powertrain Controls - ECM/PCM
CHECK: For properly installed fuel cap.
CHECK: Fuel pressure. Refer to Diagnostic Charts/Chart A-6 Fuel System Diagnosis Related Tests, Information and Procedures
CHECK: Canister for fuel loading.
CHECK: Injector balance test. Refer to Diagnostic Charts/Chart A-7 Poppet Nozzle Diagnosis of appropriate engine VIN. Chart A-7 Poppet Nozzle Diagnosis

IGNITION SYSTEM
CHECK: Ignition system, incorrect timing, or excessive advance.
CHECK: Spark plugs, plug wires, and ignition components.

ADDITIONAL CHECKS
CHECK: For vacuum leaks.
CHECK: For lead contamination of catalytic converter (look for tampered or missing fuel filler neck restrictor).
CHECK: Carbon buildup. Remove carbon with top engine cleaner. Follow instructions on can.
CHECK: EGR valve for not opening.
CHECK: Crankcase ventilation valve for being plugged, stuck or blocked crankcase ventilation hose.