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.
- 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. DTC 45
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.DTC 44