Excessive Exhaust Emissions (Odors)

DESCRIPTION
Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odors do not necessarily indicate excessive emissions.

INSPECTION
1. Perform a "Diagnostic Circuit Check".
2. If the emissions test shows excessive CO and HC or also has excessive odors, inspect the items which can cause a car to run RICH as follows; (Make sure engine is at normal operating temperature).

a. Inspect the fuel pressure. Refer to Computers and Controls / System Diagnosis / Diagnostic Charts / Chart A4-7. Chart A4-7 Fuel System Diagnosis
b. Inspect the canister for fuel loading. Refer to Diagnostic Charts / Chart C-3.
c. Inspect injector balance. Refer to Diagnostic Charts / Chart C-2A.
d. Inspect the Positive Crankcase Ventilation ([1][2]PCV) valve for being plugged, stuck, or blocked PCV hose, or fuel in the crankcase.
e. Inspect the spark plugs, spark plug wires, and ignition components.
f. Check for lead contamination of catalytic converter (look for removal of fuel filler neck restrictor).
g. Check for properly installed fuel cap.

3. If the system is running RICH (block learn less than 110), refer to Diagnostic Charts / Code 45 / Diagnostic Aids.

4. If the emissions test shows excessive NOx, inspect the items which can cause a car to run LEAN, or to run too hot.
a. Inspect the Exhaust Gas Recirculation (EGR) valve for not opening. Refer to Diagnostic Charts / Chart C-7.
b. Inspect for vacuum leaks.
c. Inspect the coolant system and coolant fan for proper operation. Refer to Diagnostic Charts / Chart C-12B.
d. Remove carbon with top engine cleaner. Follow the instructions on the can.

5. If the system is running LEAN (block learn greater than 150), refer to Diagnostic Charts / Code 44 / Diagnostic Aids.