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Part 2. The Visual Inspection
During the visual phase of the smog inspection, the smog technician or mechanic undertakes a comprehensive assessment to ensure the presence and proper connection of essential emissions components mandated by the State of California. Additionally, this segment of the smog test includes a Visible Smoke Test.
The technician's primary objective is to locate and confirm that all emissions components are not only present but also correctly connected. Beyond emissions components, the technician meticulously checks for any malfunctioning or disconnected electrical connections, vacuum hoses, or any piping that could impact engine performance and, consequently, lead to increased harmful smog emissions.
It's important to note that this stage of the smog inspection is purely visual and does not involve testing the functionality of emissions components. The technician's task is limited to visually identifying these components and ensuring their proper connection. If a vehicle does not pass the smog inspection, it becomes the owner's responsibility to have individual emissions components inspected for any damage or defects.
A. Emissions Components
Before bringing your vehicle for inspection, you can conduct a preliminary inspection at home to ensure that all hoses and wires are in place and correctly connected. The following is a list of emissions components that the smog technician will inspect:
- The Underhood Emission Label
- Exhaust Gas Recirculation Valve (EGR)
- Positive Crankcase Ventilation (PCV)
- Charcoal Canister (EVAP System)
- Catalytic Converter (CAT)
- Oxygen Sensor (O2 Sensor)
- Air Injection System (AIR)
- Carburetor Pre-Heat Tube
- Additional Emissions Components
The following emissions components are also subject to visual inspection by the technician, who must confirm their presence and proper connection. Most modern vehicles come equipped with these components:
- Air Filter & Housing
- Throttle Position Sensor (TPS)
- Engine Coolant Temp Sensor (ECT)
- Manifold Absolute Pressure (MAP)
- Crankshaft Position Sensor (CKP)
- Camshaft Position Sensor (CPS)
- Intake Air Temperature Sensor (IAT)
B. Visible Smoke Test
As part of the smog check for vehicles, there is a requirement for a visual inspection to detect excessive black or white smoke emitted from both the exhaust/tailpipe and the engine compartment.
This visual assessment is conducted in addition to the tailpipe emissions test, with the smog technician documenting their observations in the smog machine following the emissions test.
The presence of excessive smoke, whether black or white, will result in a smog check failure. If your vehicle emits visible smoke, you will need to have the issue diagnosed and repaired before it can pass the smog check. In cases of severe engine damage, smoke may emanate from the engine compartment, leading to a visible smoke test failure.
Causes of Excessive Black Smoke:
1. Inadequate fuel combustion, resulting in elevated Carbon Monoxide (CO) levels, leading to the emission of excessive black smoke from the tailpipe. Such vehicles also tend to have increased fuel consumption.
2. Engine oil infiltration into the combustion chambers, causing oil to mix with the fuel and air mixture, and subsequently producing excessive black smoke from the tailpipe. Oil seepage may be attributed to defective piston rings, valve seals, or issues with the Positive Crank Ventilation (PCV) System.
Causes of Excessive White Smoke:
Excessive white smoke typically indicates a burnt or blown head gasket. The presence of copious white smoke (resembling steam) results from water seeping into the combustion chambers. Operating at temperatures around 2500°F, the engine experiences water infiltration into the combustion chambers through the head gasket, often leading to overheating and white smoke emissions from the tailpipe.
Note: Excessive white smoke should not be confused with the normal white smoke emitted during cold weather or engine startup. The smog check program acknowledges that vehicles may emit white smoke when cold and ensures that a vehicle is adequately warmed up before conducting the smog test.
White smoke during startup or in cold weather is merely steam and does not lead to a smog check failure.