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, vapor from expanding fuel in fuel tank collect in expansion tank. From the expansion tank, vapor flows out of tank and into charcoal canister through liquid/vapor separator. Manifold vacuum then pulls vapor from canister into combustion chamber for burning when engine is running.
When ignition is off or engine is being cranked, the ECM keeps the bowl vent solenoid valve closed to allow float bowl vapor to flow to canister.
When engine is running, the ECM opens the bowl vent solenoid valve to allow float bowl vapor to flow through inner vent passage into carburetor bore.
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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