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. Refer to Diagnostic Aids for DTC P0132 in Diagnostic Trouble Code Charts/Diagnostic Trouble Code P0132. P0132

 IF Emission test shows excessive NOx, see Chart C-7, Exhaust Gas Recirculation (EGR) Flow Check. Chart C-7 Exhaust Gas Recirculation (EGR) Flow Check

Also check items which could cause vehicle to run lean or too hot. Refer to Diagnostic Aids for DTC PO131 in Diagnostic Trouble Code Charts/Diagnostic Trouble Code P0131. P0131

COOLING SYSTEM
If the scan tool indicates a very high engine coolant temperature and the system is running lean:

- Check: Engine coolant level.
- Check: Engine thermostat for faulty part (always open) or for incorrect heat range.
- Check: Cooling fan operation, use Chart C-12A, Cooling Fan Check. Chart C-12A Coolant Fan Functional Check

FUEL SYSTEM
Check:
^ For properly installed fuel cap.
^ Fuel pressure. Use Chart A-7, Fuel System Diagnosis. Related Tests, Information and Procedures

^ Injector balance test. Use Chart C-2A, Injector Coil/Balance Test Procedure. Chart C-2A Injector Coil Balance Test Procedure

^ Evaporative Emissions (EVAP) fuel canister for fuel loading. Use Chart C-3, Evaporative Canister Purge Valve Check. Chart C-3 EVAP Canister Purge Valve Check


NOTICE:
^ If the system is running rich, Long Term (L.T.) fuel trim below 110 with canister purge solenoid disconnected, refer to Diagnostic Aids for DTC PO132 in Diagnostic Trouble Code Charts/Diagnostic Trouble Code P0132. P0132

^ If the system is running lean (L.T. fuel trim above 150) refer to Diagnostic Aids for DTC PO131 in Diagnostic Trouble Code Charts/Diagnostic Trouble Code P0131. P0131

IGNITION SYSTEM
Check spark plugs, plug wires, and ignition components.

ADDITIONAL CHECKS
Check:
^ 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.
^ Check: Crankcase ventilation valve for being restricted or stuck or fuel in the crankcase.
^ For correct Programable Read Only Memory (PROM).