Excessive Odors - Fuel, Emissions

SYMPTOM
Vehicle fails an emission test or vehicle has excessive "rotten egg" smell. Excessive odors do not necessarily indicate excessive emissions.
^ Check for EGR valve opening, refer to PCM code 32.
^ Check for faulty cooling system components (fan, thermostat, PCM sensor).


SYMPTOM
If fuel system is running rich (block learn less than 118):
^ Check for rich fuel system, refer to PCM Code 45 and diagnostic chart.


SYMPTOM
If fuel system is running lean (block learn more 138):
^ Check for Lean fuel system, refer to PCM code 44 and diagnostic chart.


SYMPTOM
If emissions test indicates excessive N02, check for items which cause vehicle to run lean or too hot, refer to diagnostic chart and emission symptom chart


SYMPTOM
If emission test indicates excessive HC and CO or exhaust has excessive odors, check for items which cause vehicle to run rich, refer to diagnostic chart, emission symptom chart and check for:

1. Incorrect fuel pressure.

2. Fuel loading of evaporative vapor canister.

3. PCV valve plugging, sticking, or blocked [1][2]PCV hose. Check for fuel in crankcase.

4. Catalytic converter lead contamination, check exhaust backpressure and removal of filler neck gas pump nozzle restrictor.

5. Improper fuel cap or damaged seal.

6. Vapor canister hose connections, condition and routings. Also inspect the vehicle's hood and front of dash seals for damage.

7. Faulty spark plugs, wires, coil/module or ignition components.

NOTE: Use of an emissions analyzer may help in locating points of fuel odor emissions. Even small amounts of fuel vapor will cause high levels of hydrocarbons to be indicated by the emissions analyzer. Slowly move the analyzer probe near the suspect area. The hydrocarbon level will increase as the point of emissions is approached. The probe must be moved slowly, as it takes time for the gases to travel through the tester's hose.