The Best Auto Emission System & Accessories

Buying Guide

Gasoline-powered vehicles produce fumes that evaporate from fuel tanks, leading to hydrocarbon pollution. This pollution is why many vehicles, especially older ones, have to go through those emission-check facilities from time to time. If you weren’t aware, the pollution continues to go into the atmosphere even when engines are not running.

A vehicle’s evaporative emission control system (EVAP) prevents gas vapors from leaking out into the air from the fuel system and fuel tank. Lest you think this is new-age environmentalism in action, regulations have required these EVAP systems on gas-powered cars and trucks since the 1970s.

An EVAP system usually has a fuel tank, a vapor-storage canister, hoses, valves, vent lines and a fuel-tank gas cap. Those lines travel from the fuel tank to the canister, where they are trapped and stored. Once the engine is warmed up, the vapors are drawn into the intake manifold, where the engine burns them off. You may need to replace any of the working parts when the system malfunctions.

The signs of EVAP system problems include the infamous “Check Engine” light, a worrying gasoline smell in or outside the vehicle, a loss of engine performance, and increased gas consumption. Remember that any of these can also be red flags for other issues. Electric devices can diagnose EVAP problems; mechanics use them, but you can also buy one of your own as long as you know how to use it properly.

Should you need to purchase replacement EVAP parts, you can always get them from your vehicle’s manufacturer and have one of their mechanics install them. You’ll likely be paying top dollar for these services, though.

Buying aftermarket auto parts will save you a lot of money, but make sure that they are compatible with your vehicle. Some of the manufacturers have online tools where you can input your make and model to see if the part will work. If you aren’t comfortable installing these parts, buy them yourself and have a licensed mechanic do it.

• Before buying aftermarket auto parts, check with the dealer first to see what they charge for them; that way, you’ll have a baseline when shopping.
• If you find the needed part but aren’t familiar with the seller, visit the company’s website, read the reviews and check their return policies.
• Auction sites like eBay also have aftermarket auto parts, but they have no-return policies in many cases.
• If you’ve never heard of an online parts manufacturer or outlet, look for a contact phone number and a company return policy.
• Know how engines work before buying anything. In this case, find a diagram of a vehicle EVAP system and go from there.