What may surprise you is that many new vehicles are being designed without gas … The valve is set to balance the pressure with the surrounding atmosphere. Your email address will not be published. Copyright 2020 Leaf Group Ltd. / Leaf Group Media. As I mentioned before, this is … The vented gas cap is designed to vent small amounts of air into the car gas tank line. Open the fuel door on your vehicle.

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Save my name, email, and website in this browser for the next time I comment. A missing cap certainly causes those same issues, but also you run the risk of burning down your ride. The gas cap has air vents to allow the air to enter into the tank to maintain pressure.

In addition, it leaks gas out of the vented cap when cornering if the tank is more than 1/2 full. The vented gas cap has a chamber under the plastic cap handle that inserts into the fuel fill line. So this is the part I’m discussing here, the locking stock cap. On each side of the chamber are small openings where air is able to enter. To submit your questions or ideas, or to simply learn more about It Still Works, contact us.

If the rubber seal on the fuel cap isn’t sealing, because the cap is loose or cross threaded, the test fails. I/M 240 emission test procedures require testing the gas cap to make sure it is fully functional.

Beginning in 1971, US-licensed cars had to have evaporative controls built into the fuel system, and this all starts with the gas cap. Know-How Notes: Why You Need To Check Your Gas Cap, How To Use Sea Foam: Three Ways To A Cleaner Fuel System, Dead Car Battery?

That often forgotten (usually on the pump) hunk of plastic that keeps the boom-boom juice from spilling on the road when you punch the pedal to make the light. If your “Check Engine” light is on and you think it may be caused by your fuel cap, it should go away with a few days of driving once the cap is secured. Air is allowed in, but no fumes are allowed out of the gas cap, because of environmental concerns. Here Are the Warning Signs, How to Remove a Seized Lug Nut in 3 Easy Steps, 6 Signs You May Have a Bad Water Pump On Your Hands, Sudden Soft Brakes: Don't Panic With These 3 Tips, How to Jump-Start a Diesel Truck With Two Batteries, If Your Car Battery Won't Hold a Charge, Try These 4 Steps, Ron Capps Closes 2020 Season with Final-Round Appearance and Fourth-Place Ranking, Elliott Secures Championship 4 Berth with Win at Martinsville Speedway, Ron Capps Races to Runner-Up Finish in Houston, Sweet to Enter Championship Weekend with 46-Point Lead after Trouble at Kokomo, Ron Capps Records Semifinal Finish in Dallas. The most common cause of a lit check engine light is not a bad sensor, it is a loose gas cap. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. Checking your fuel cap takes only a few seconds after each fill-up. A modern gas cap serves several functions. When the pressure reaches a certain point (defined by so many pounds per square inch) the valve opens by a very small amount, relieving some of the pressure.

What may surprise you is that many new vehicles are being designed without gas caps at all.

Required fields are marked *. Today’s fuel systems require a complete seal on the tank, without it, there can be issues. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more.

The vented gas cap has a one-way release valve that is pressure-activated. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced. THE STOCK DR650SE GAS CAP… The real purpose of this thread is to share the disassembly process of the stock gas cap and show you what had plagued this bike for a number of years.

Historically, the gas cap was simply a way to plug the hole in the tank, but all of that changed in 1970, when safety concerns and the EPA brought some much needed issues to light. By the mid 90s, fuel vapor controls were 50 times more strict than in 1971. A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. In fact, a missing or incorrectly installed gas cap can cost you as much as 30 gallons over the course of a year. These chambers lead to the pressure valve, which, as the level in the tank decreases, allows air inside to remove any possibility of a vacuum forming. That is a substantial amount of fuel. For more information on why you need to check your gas cap, chat with a knowledgeable expert at your local NAPA AUTO PARTS store. Instead of a traditional cap, there is self-latching seal door that prevents the vapors from escaping. I got rid of the old cap and replaced it with a new vented cap and it still leaks a bit but less. Ever wonder why some cars have a sticker inside the gas cap door that says “open slowly” that is there to control the vapor release on hot days.