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
If emission test shows excessive CO and HC, check items which cause the vehicle to run RICH (long term fuel trim near 115), refer to "Diagnostic Aids" in DTC 43 or 45.
If emission test shows excessive NOx, check items which cause vehicle to run lean or too hot.

COOLING SYSTEM
If the Tech 1 indicates a very high engine coolant temperature and the system is operating lean:
- CHECK: Engine coolant level, use Chart C-16. Testing and Inspection
- CHECK: Engine thermostat for faulty part or for wrong heat range.
- CHECK: Cooling fan operation, use Chart C-12. Testing and Inspection

FUEL SYSTEM
NOTE: If the system is running rich (long term fuel trim near 115), refer to "Diagnostic Aids" in DTC 43 or 45.

If the system is running lean (long term fuel trim near 160) refer to "Diagnostic Aids" in DTC 42 or 44. Refer to "Diagnostic Aids" in DTC 46. Testing and Inspection

Check:
For properly installed fuel cap.
Fuel pressure, use Chart A-7. Testing and Inspection
Injector balance test, use Chart C-2A. Testing and Inspection
Evaporative Emissions (EVAP) canister for fuel loading, use Chart C-3. Testing and Inspection

IGNITION SYSTEM
Check:
Spark plugs, ignition wires and ignition components.

ADDITIONAL CHECKS
Check:
For vacuum leaks.
For lead contamination of three-way catalytic converter (look for the removal of fuel filler neck restrictor).
Carbon buildup. Remove carbon with top engine cleaner. Follow instructions on can.
Crankcase ventilation valves for being plugged, stuck or blocked crankcase ventilation hose or fuel in the crankcase.
For correct Programmable Read Only Memory (PROM) (see Service Bulletins).
For contaminated fuel or poor quality fuel.