Excessive Exhaust Emissions or Odors
Checks
| Action
|
DEFINITION: The vehicle fails an emission test. The vehicle has an excessive
rotten egg smell. Excessive odors do not necessarily indicate excessive emissions.
|
Preliminary Checks
|
| • | Refer to
Symptoms
for the
Important Preliminary Checks. |
| • | Make sure engine is at the normal operating temperature. |
| • | Check the emission test in order to see if it shows excessive
HC, CO, and other items which cause the vehicle to run Rich (The Long Term
Fuel Trim will be less than 115). Refer to the Diagnostic Aids in
DTC 45 Rich Exhaust Indicated
. |
| • | Check the emission test to see if it shows excessive NOx which
will cause the engine to run Lean (The Long Term Fuel Trim will be greater
than 150). Refer to the Diagnostic Aids in
DTC 44 Lean Exhaust Indicated
. |
|
Sensor Check
| Check the scan tool for a very high coolant temperature.
Check the cooling system and the coolant fan for proper operation. Refer
to the appropriate service manual.
|
Fuel System Checks
|
| • | Check for the system running Rich (The Long Term Fuel Trim will
be less than 115). Refer to the Diagnostic Aids in
DTC 45 Rich Exhaust Indicated
. |
| • | Check for the system running Lean (The Long Term Fuel Trim will
be greater than 150). Refer to the Diagnostic Aids in
DTC 44 Lean Exhaust Indicated
. |
|
Ignition System Checks
| Check the ignition system for incorrect timing,
or excessive advance. Refer to
Distributor Ignition (DI) System Check
.
Check the spark plugs, the plug wires, and the ignition components.
Refer to Engine Mechanical.
|
Additional Checks
|
| • | Check for vacuum leaks. |
| • | Check for lead contamination of the catalytic converter (Look
for the removal of the fuel filler neck restrictor). |
| • | Check for carbon buildup in the engine. Remove the carbon with
a top engine cleaner. Follow the instructions on the can. |
|
