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 and oxygen
sensor voltage is less than .5 volts, refer to
COMPONENT TESTS to test the oxygen sensor.
If the system is running lean and the oxygen
sensor voltage is greater than .5 volts, refer to
COMPONENT TESTS to test the oxygen sensor.
CHECK: ^ For properly installed fuel cap.
^ FUEL PRESSURE:






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: Plugged or stuck PCV valve,
blocked PCV hose, fuel in the crankcase,
or malfunctioning PCV solenoid.
^ EGR SYSTEM: Valve not opening, or open
all of the time.
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.