Excessive Exhaust Emissions (Odors)

Definition: Vehicle fails an emission test. May also have excessive "rotten egg" smell (hydrogen sulfide). Excessive odor does not necessarily indicate excessive emissions.
- Perform "Diagnostic Circuit Check". Testing and Inspection
IF TEST SHOWS EXCESSIVE CO AND HC, (or also has excessive odors):
- Check items which cause engine to run RICH.
- Make sure engine is at normal operating temperature.
- CHECK:
- Fuel pressure. See CHART A-6. Chart A-6 Fuel System Pressure Test
- Incorrect timing. See "Vehicle Emission Control Information" label on vehicle.
- Canister for fuel loading.
- PCV valve for being plugged or stuck, or blocked PCV hose.
- Spark plugs, plug wires, and ignition components.
- Check for lead contamination of catalytic converter (look for removal of fuel filler neck restrictor).
- Presence of fuel in crankcase.
- Check for improperly installed fuel cap.
If the system is running rich, (block learn less than 118), refer to "Diagnostic Aids" on text of Code 45. Powertrain Controls - ECM/PCM
IF TEST SHOWS EXCESSIVE NOX:
- Check items which cause engine to run LEAN, or to run too hot.
- EGR valve for not opening. See "EGR System Check" under C Charts. Testing and Inspection
- Vacuum leaks.
- Remove carbon with top engine cleaner. Follow instructions on can.
- Check ignition timing for excessive base advance. See "Vehicle Emission Control Information" label on vehicle.
- Coolant system and coolant fan for proper operation.
If the system is running lean, (block learn greater than 138), refer to "Diagnostic Aids" on text of Code 44.Powertrain Controls - ECM/PCM