Fuel Shut-Off Valve Construction/Operation; Construction; Operation; Rollover Valve Function - Mazda RX-8 2004 Service Highlights

FUEL SHUT-OFF VALVE CONSTRUCTION/OPERATION

Construction

• Since the shut-off valve is press-fit to the top of the fuel tank, it cannot be disassembled.
• The shut-off valve mainly consists of a valve, float, spring, and by-pass valve.

Operation

• During refueling or due to fuel sloshing, the float is flooded with fuel and the floating force causes the valve to
close. Also, during vehicle rollover, the valve closes due to balance between the float gravity and spring
pressure.
• The float rises during refueling, locks after refueling is completed, and returns to the original position by its own
weight when the fuel level decreases. Due to this, the evaporative emissions in the fuel tank can be released
through the charcoal canister.
TO CHARCOAL
CANISTER
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ROLLOVER VALVE FUNCTION

Function

• The rollover valve prevents fuel from flowing to the charcoal canister during tight turns, vehicle rollover or when
the fuel tank is full.
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EMISSION SYSTEM
OPEN
TO CHARCOAL
CANISTER
VALVE
FLOAT
SPRING
:EVAPORATIVE GAS FLOW
CHU011642990S02
SHUT OFF
CHU0116S020
CHU011642720S01
01–16–11
01–16