Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Evaporation System: Operation
When engine is not running, fuel vapor from fuel tank is directed to charcoal canister for storage. The tank pressure control valve is closed to prevent vapor from escaping into atmosphere. At the same time, the vent switching valve is open, allowing fuel vapor from float bowl to enter charcoal canister for storage.
When engine is running, the vent switching valve closes and manifold vacuum opens the tank pressure control valve. This allows fuel vapor from fuel tank and charcoal canister to flow to intake manifold to be burned by the engine.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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