Excessive Exhaust Emissions (Odors)
EXCESSIVE EXHAUST EMISSIONS OR ODORSDefinition
Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odors do not necessarily indicate excessive emissions.
^ Perform "Diagnostic Circuit Check." Testing and Inspection
NOTE: IF EMISSION TEST shows excessive CO and HC, check items which cause car to run rich (Long Term Fuel Timing less than 110); refer to "Diagnostic Aids" of DTC 45. Testing and Inspection
NOTE: IF EMISSION TEST shows excessive NOx, check items which cause car to run lean or too hot.
^ CHECK: For vacuum leaks.
^ CHECK: FOR valve for not opening.
^ CHECK: For lead contamination at catalytic converter (look for the removal of fuel filler neck restrictor).
^ CHECK: Carbon build-up. Remove carbon with top engine cleaner. Follow instructions on can.
^ CHECK: PCV valve for being plugged or stuck or fuel in the crankcase.
^ CHECK: Spark plugs, plug wires, and ignition components.
^ If the "Scan" tool indicates a very high coolant temperature and the system is running lean:
^ CHECK: Engine coolant level.
^ CHECK: Engine thermostat for faulty part (always open) or for wrong heat range.
NOTE: If the system is running RICH (block learn near 110), refer to "Diagnostic Aids" of DTC 45. If the system is running LEAN (block learn near 150) refer to "Diagnostic Aids" of DTC 44. Testing and Inspection
^ CHECK: For properly installed fuel cap.
^ CHECK: Fuel pressure.
^ CHECK: Injector balance test.
^ CHECK: Canister for fuel loading.
Computer Related Failures:
^ Check:
- EGR valve opening, refer to PCM code 32. Testing and Inspection
- Faulty cooling system components (fan, thermostat, PCM sensor).
^ If fuel system is running rich (long term fuel trim less than 118):
- Rich fuel system, refer to PCM code 45 and diagnostic chart. Testing and Inspection
^ If fuel system is running lean (long term fuel trim more than 138):
- Lean fuel system, refer to PCM code 44 and diagnostic chart. Testing and Inspection
^ If emissions test indicates excessive NOx, check for items which cause vehicle to run too lean or too hot.
^ 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:
- Incorrect fuel pressure.
- Fuel loading of EVAP vapor canister.
- PCV valve plugging, sticking, or blocked PCV hose. Check for fuel in crankcase.
- Three way catalytic converter lead contamination, check exhaust backpressure and removal of filler neck gas pump nozzle restrictor.
- Improper fuel cap or damaged seal.
- EVAP vapor canister hose connections, condition and routings. Also inspect the vehicle's hood and front of dash seals for damage.
- Faulty spark plugs, wires, coil/module, converter 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.