Excessive Exhaust Emissions (Odors)

DEFINITION: Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell.

NOTE: Excessive odors DO NOT necessarily indicate excessive emissions.

^ You should start with Flow of Diagnosis, under Testing and Inspection.
^ If test shows excessive CO and HC, (or also has excessive odors), check items which cause car to run rich.
- Make sure engine is at normal operating temperature.
- Visually check hoses for splits, kinks or improper connections.
- Remove air cleaner and check air filter for dirt or restricted air flow. Replace as necessary.
- Check for misadjusted idle mixture if tamper-proof plugs are removed.
- Check choke valve and linkage for sticking or faulty operation.
- Check choke, vacuum breaks and fast idle adjustments.
- Check for stuck PCV valve or obstructed hose.
- Check for lead contamination of catalytic converter. Check for absence of filler neck restrictor.
- Check operation of air management system (AIR system).
- Check for properly installed fuel cap.
- Check carburetor for flooding.
- Check for fuel in the crankcase.
- Check float level using external float gauge.
- Check canister for loading and check purge system for proper operation.
- Check for incorrect idle speed.
- Check for incorrect timing. See Vehicle Emission Control information label.
- Check condition of spark plugs, plug wires and distributor cap.
^ If test shows excessive NOx, check items which cause car to run lean, or to run too hot.
- Check EGR valve for not opening.
- Check for vacuum leaks.
- Check for proper operation of TCA.
- Check coolant system and coolant fan for proper operation.
- Remove carbon with top engine cleaner. Follow instructions on can.
- Check ignition timing for excessive base advance. See Vehicle Emission Control Information label.