Excessive Exhaust Emissions (Odors)

DEFINITION
Vehicle fails an emission test. May also have excessive "rotten egg" smell (hydrogen sulfide).

POWERTRAIN SYSTEM CHECK
Perform Chart 1: Powertrain System Check. Chart 1 Powertrain System Check

MECHANICAL CAUSES
Check for the following mechanical causes:

^ Throttle body deposits
^ Fuel in crankcase
^ Worn piston rings
^ Vacuum leaks in intake manifold
^ Engine overheating
^ Carbon build-up
^ Air restrictions to intake manifold

PCV SYSTEM
Perform Positive Crankcase Ventilation ([1][2]PCV) system check.

EVAPORATIVE EMISSIONS (EVAP) SYSTEM CHECK
Perform Chart 6EC-1 EVAP System Check. Chart 6EC-1 EVAP System Check

EXHAUST GAS RECIRCULATION (EGR) SYSTEM CHECK
Perform Chart 6EC-2 EGR System Check. Chart 6EC-2 EGR System Check

EXHAUST SYSTEM
Perform exhaust diagnosis looking in particular for:

^ Restricted exhaust

FUEL SYSTEM CHECK
Perform Chart 6C-1 Fuel System Check. Check especially for:

^ Fuel Quality
- water content
- sour fuel
^ Leaking fuel injectors
^ Incorrect fuel pressure

Chart 6C-1 Fuel System Check

IGNITION SYSTEM CHECK
Perform Chart C-1 Ignition Control Performance Test. Check especially for:

^ High resistance, open, shorted, or arcing spark plug wires, crossfire between spark plug wires
^ Contaminated or damaged spark plugs
^ Distributor grounding points clean and tight
^ Correct ignition timing
^ Faulty ignition coil or Ignition Control (IC) module
^ Distributor cap, rotor, brush and button for moisture, cracks, dust or carbon tracking
^ Worn or loose distributor shaft gear
^ Bent distributor shaft or worn distributor shaft bushing

C Charts