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
^ Perform On-Board Diagnostic System Check.
^ IF EMISSION TEST shows excessive CO and HC check items which cause vehicle to run RICH (Long term fuel trim memory less than 58). Refer to Diagnostic Aids in text of Diagnostic Trouble Code (DTC) 45. Powertrain Controls - ECM/PCM
^ For correct EPROM. See Service Bulletins.

IGNITION SYSTEM CHECKS
Check spark plugs and ignition components. Refer to Ignition System. Ignition System

COOLING SYSTEM
If the scan tool indicates a very high engine coolant temperature and the system is running lean:
- Engine coolant level.
- CEngine thermostat for faulty part (always closed) or for incorrect heat range.
- Cooling fan operation, use CHART C-12. Chart C-12 Coolant Fan Functional Check

FUEL SYSTEM CHECKS
^ If the system is running rich (long term fuel trim near 58), refer to Diagnostic Aids in text of DTC 45. Powertrain Controls - ECM/PCM
If the system is running lean (long term fuel trim near 198), refer to Diagnostic Aids in text of DTC 44. Powertrain Controls - ECM/PCM
^ For properly installed fuel cap.
^ Fuel pressure. Use CHART A-7. Related Tests, Information and Procedures
^ Injector balance test. Use CHART C-2A. Chart C-2A Injector Coil Balance Test Procedure
^ Evaporative Emissions (EVAP) fuel canister for fuel loading. Use CHART C-3. Chart C-3 EVAP Canister Purge Valve Check

ADDITIONAL CHECKS
^ For vacuum leaks.
^ For lead contamination of catalytic converter (look for the removal of fuel filler neck restrictor).
^ Carbon buildup. Remove carbon with top engine cleaner. Follow instructions on can.
^ Exhaust Gas Recirculation (EGR) operation. See Chart C-7. Chart C-7 Exhaust Gas Recirculation (EGR) System Check