Excessive Exhaust Emissions (Odors)

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

Check Powertrain System, if not already completed

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



Check PCV System.

Check EVAP Components.

Check EGR System.

Check Exhaust, looking in particular for:

- Restricted Exhaust



Check Fuel System, looking in particular for:

- Fuel Quality
- Water Content
- Sour Fuel
- Leaking Fuel Injectors

- Incorrect Fuel Pressure


Check Ignition System, 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 IC Module