Emissions Control Systems

Emission control system is a catch-all term that includes those pieces and parts of your vehicle that are responsible for reducing air pollution.

Clean air is the target of municipal authorities around the country and, no big surprise; engines that consume petroleum are at the heart of the problem. As a result, emission standards are in place which require specialized equipment in order to help insure clean air.

Emission pollutants arise from mainly three sources; crankcase emissions; evaporative emissions and tailpipe exhaust emissions. Crankcase emissions consist of unburned fuel and combustion byproducts. These gases are recirculated back into the engine for reburning by the Positive Crankcase Ventilation (PCV) valve…an emissions control device that routes unburned crankcase blowby gases back into the intake manifold where they can be reburned. The PCV system is one of the oldest and most valuable emission control devices. In addition to stopping crankcase emissions (and thus reducing air pollution), the PCV valve moves air through the crankcase which helps eliminate moisture - a leading contributor to sludge. Thus the PCV valve extends the life of the oil and engine. The PCV valve requires very little maintenance…the valve and filter should be replaced somewhere around 30,000 to 50,000 miles (check your owner’s manual for service intervals).

Evaporative emissions are the fuel vapors that seep out of the fuel tank and carburetor. They are prevented from escaping into the atmosphere by sealing the fuel system and storing the vapors in a vapor canister for later reburning.

Tailpipe exhaust emissions consist of carbon monoxide (CO), unburned hydrocarbons (HC) and oxides of nitrogen (NOX). To a degree, these pollutants are minimized by various engine design features, careful control of fuel calibration and ignition timing, and the EGR or exhaust gas recalculation system.

Frequently we determine that carbon is building up in the intake manifold and thus blocking the EGR valve. Unfortunately gasoline additives are not capable of removing the buildup. The only way we know to clean this is by removing the manifold and mechanically scraping the carbon out.

The pollutants that make it into the exhaust are “reburned” by the catalytic converter before they exit the tailpipe. If you ever watch your vehicle go through its annual safety inspection, you’re familiar with the gas cap pressure check. This test determines the ability of your gas cap to keep fuel vapors in your tank rather than let them escape into the atmosphere.

The emission control system is an integral part of the engine, and should not be tampered with or disconnected. This is especially true on vehicles with computerized engine controls and/or those required to pass emissions testing.

In summary, failure to maintain emission control systems has several drawbacks:

  • It darkens the Dallas skyline, contributes to air pollution and aggravates respiratory problems.

  • It degrades your vehicle’s performance and in some cases can leave you stranded.

  • It can cause you to fail your annual vehicle inspection.

So for clean air, easy breathing, new car performance and a passing safety inspection grade, regular testing of your emissions control system is a must.

At Dallas Auto Sports, we have the tools and experience to keep your system in compliance with local and state standards. For an appointment call 214.320.2228.

Auto service and repair for: Audi, BMW, Mercedes, Land Rover, Lexus, Jaguar, Porsche, VW, Volvo, Saab, and more. Servicing cars from the Dallas, Plano, Richardson and the DFW Metroplex area.