During the visual inspection, inspectors are required to inspect the fuel filler cap for signs of tamper. Signs of tampering can be obvious in many instances. Ensure the fuel cap fits properly, and shows no signs of physical damage.
A Gas Cap Tamper may be present if the rubber gasket on the gas cap is dried and cracked. In this case, the vehicle must be failed.
Keep in mind that there may exist more than one fuel tank on the vehicle. If you find that this is the case, every gas cap will need to be visually inspected. The only exception to this requirement is fuel tanks that are generators on motor homes do not need to be inspected.
If a Fuel Inlet Restrictor is missing or appears damaged, it may have been tampered with. The main reason to tamper with a fuel inlet restrictor is to run leaded gasoline. Since Leaded Gasoline has been outlawed and is not sold in the US, fuel inlet restrictors are rarely tampered with.
New technology for fuel caps appear in some 2008 and newer model vehicles where the fuel cap has been replaced with an Easy Fuel capless fuel filter system. In this case, what you will find in place of a fuel cap is a “flapper door” by which the fuel nozzle is inserted directly into the tank. Once the nozzle is removed the flapper door seals the tank. These capes systems will be clearly marked and identifiable.