Excessive Exhaust Emissions (Odors)

SYMPTOM DESCRIPTION:
Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odors do not necessarily indicate excessive emissions. For further diagnosis by symptom and testing of emission components refer to EMISSION CONTROLS.



SYSTEM OR COMPONENT TO CHECK ACTION

COMPUTER INPUTS/OUTPUTS NOTE: ^ If the "Scan" tool indicates
a very high coolant temperature and the
system is running LEAN: Check the Cooling
System and Cooling Fan for proper operation.



FUEL NOTE: ^ If the system is running rich,
(block learn less than 115), refer to
"DIAGNOSTIC AIDS" in DIAGNOSTIC CHARTS/
TROUBLE CODE CHARTS/CODE 45.
If the system is running lean,
(block learn greater than 150), refer to
"DIAGNOSTIC AIDS" in DIAGNOSTIC CHARTS/
TROUBLE CODE CHARTS/CODE 44.
CHECK: ^ For properly installed fuel cap.
^ FUEL PRESSURE:
Refer to CHART A-6 in DIAGNOSTIC CHARTS/A-CHARTS.






EMISSIONS CHECK: ^ EVAPORATIVE SYSTEM: Canister for fuel loading.
^ CATALYTIC CONVERTER: For lead contamination
of catalyst (look for the removal of fuel pipe
restrictor).
^ PCV SYSTEM: Valve for being plugged, stuck,
or blocked PCV hose, or fuel in the crankcase.
^ EGR SYSTEM: Valve not opening.
NOTE: Refer to EMISSION CONTROLS for testing procedures.





IGNITION CHECK: ^ For incorrect timing or excessive advance.
^ Spark plugs, plug wires, and ignition components.





ENGINE CHECK: ^ Vacuum leaks.
^ Fuel in crankcase.
^ Carbon build-up. Remove with top engine cleaner.