How does the fuel evaporative canister work?
The EVAP system uses the charcoal canister to store fuel vapors that escape the cas tank through a tube. The charcoal (EVAP_ canister empties by engine vacuum sucking the vapors out, to be burned as fuel. This can only be done when the vent valve and purge valve are opened simultaneously. When the vent valve and purge valve are closed, the evaporative canister will store vapors until the vents are opened. This allows environmentally harmful fuel vapors from entering the atmosphere, and increases fuel mileage over a tank of fuel.
What are the symptoms related to a bad fuel evaporative canister?
The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the
check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. The canister may also cause difficulty starting the engine, a
rough idle, and poor fuel mileage.
Can I drive with a fuel evaporative canister problem?
A vehicle with an EVAP system issue can be driven, but may achieve lower fuel mileage. Also, a vehicle with an EVAP system issue will not pass standardized state or federal emission testing. The vehicle may take time to start and idle rough, but driving the vehicle should not be an issue.
How often do fuel evaporative canisters need to be replaced?
EVAP system faults are very common, and happen throughout the useful life of the vehicle. The evaporative canister and all other components in the system are linked to the same trouble codes, so all components are inspected when the system has a fault. This includes the filler cap, a.k.a. gas cap. The
gas cap is the number one reason EVAP failures are recorded. These codes are preventable with regular cleaning and inspection of the fuel cap.