Excessive Exhaust Emissions (Odors)

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

POWERTRAIN SYSTEM
Perform Powertrain System Check, if not already completed. Chart 1 Powertrain System Check

MECHANICAL CAUSES
Check for the following mechanical causes:

^ Oxygen Sensor Heaters Inoperative.
- Check for battery voltage between pins B and D (harness side) at each oxygen sensor with ignition "ON." Repair if no voltage.
- Measure resistance between pins B and D (sensor side) at each oxygen sensor. Resistance should be between 3 and 15 ohms. Replace oxygen sensor if resistance is greater than 15 ohms or less than 3 ohms.
^ Vacuum Leaks in Intake Manifold System
^ Engine Overheating
^ Carbon Build-Up
^ Air Restrictions to Intake Manifold

POSITIVE CRANKCASE VENTILATION SYSTEM
Perform PCV System Check. Positive Crankcase Ventilation

EVAPORATIVE EMISSIONS (EVAP)
Perform functional tests of EVAP components. Evaporative Emissions System

EXHAUST GAS RECIRCULATION
Check EGR System. Refer to Chart 6EC-1 EGR System Check. Chart 6EC-1 EGR System Check

EXHAUST DIAGNOSIS
Check exhaust system looking In particular for:

^ Restricted Catalytic Converter or Exhaust

FUEL SYSTEM
Perform Chart 6C-1 Fuel System Check looking in particular for:

^ Fuel Quality
- Water Content
- Sour Fuel
- Leaking Fuel Injectors
^ Incorrect Fuel Pressure
^ Plugged or dirty Fuel Filter

Chart 6C-1 Fuel System Check

IGNITION SYSTEM
Perform Chart 1 Ignition System Check, looking in particular for:

^ High Resistance, Open, Shorted, or Arcing Spark Plug Wires, crossfire between spark plug wires
^ Contaminated or Damaged Spark Plugs
^ Faulty Coil Pack or Ignition Control (IC) Module

Chart 1 Ignition System Check