Excessive Exhaust Emissions (Odors)

SYMPTOM DESCRIPTION:
Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odors do not necesarily 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 "Diagnotic Mode" indicates
a very high coolant temperature and the
system is running LEAN: Check the Cooling
System and Cooling Fan for proper operation.



FUEL NOTE: To determine if the condition is caused by
a lean system, the vehicle should be driven at the
speed of the complaint. If closed loop is achieved,
the fuel system has to checked for rich, lean or
improper fuel control. The DFI system has ECM
parameter ED19 "Integrator" which monitors the
oxygen sensor rich lean status and drives the fuel
system richer if the 02 sensor is lean or
leaner if the sensor is rich.
To help identify the problem
Refer to DFI SYSTEM CHECK. Or codes E44, EO44
for lean conditions and E45, EO45 for rich
NOTES ON INTERMITTENTS
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.