Fuel Cap

Fuel Cap Testing

A fuel cap protects your fuel supply by providing a cover for the tank. The cap also controls the pressure and fumes within your fuel tank.  Without proper control of the fuel pressure in the tank the engine could either starve for fuel, or flood with fuel, depending on the situation.  The cap is designed to prevent fuel loss, maintain the correct pressure and keep out contamination. Making sure your cap is secured tightly will help decrease fuel loss from evaporation and help avoid unnecessary trips to the shop to only be told your cap was left loose.

Fuel Cap Failure Results in an Arizona Emissions Test Failure:

If your Check Engine light comes on, or if you are using fuel at a higher rate than usual, there is a chance that your fuel system needs testing. Without a properly functioning seal on the fuel tank, gas will evaporate and reduce your fuel efficiency by up to 2%. If ignored long enough, you could eventually see damage to your fuel pump and filters. The engine’s computer will see the drop in fuel tank pressure and alert you with a dash light.  Failure to tighten the cap completely is the number one cause of a related engine light.  Remember to tighten until you feel 3-4 good clicks.

From a safety standpoint there is a small risk, but you could run out of gas and be stranded. From an environmental point of view, a leaky fuel system will cause gas to evaporate into the atmosphere and increase your carbon footprint. In conclusion, simple things like this can lead to larger issues and should be addressed quickly.