FUEL PUMP UNIT CONSTRUCTION/OPERATION


BHE011413350T04

Fuel Pump Unit

• Mainly consists of a fuel filter (high-pressure), pressure regulator, fuel pump, fuel reserve cup, fuel filter (low-pressure), and fuel pump (transfer).

• A pressure regulator is built-in due to the adoption of a returnless fuel system.

• A hard-plastic fuel pump unit, with an integrated fuel filter (high-pressure) and fuel pump, has been adopted to simplify the fuel line.

• The fuel pump unit, located on top of the fuel tank, can be removed and installed through the service hole in the bottom of the left side rear seat.

• The fuel pump unit cannot be disassembled.

• Fuel in the fuel reserve cup is suctioned out through the fuel filter (low-pressure) by the fuel pump, and pumped to the fuel filter (high-pressure). Return fuel is sent back to the fuel reserve cup or the fuel tank through the jet pump.

• A venturi, located in the path of fuel returning from the pressure regulator, creates negative pressure that is used to transfer fuel from the reserve to the main tank.

• If return fuel pressure exceeds the specified value, the relief valve discharges return fuel into the fuel pump unit without passing it through the venturi. Due to this, return fuel pressure is maintained below the specified value.

Pressure Regulator

• Built into the fuel pump unit due to adoption of a returnless fuel system.

• Cannot be removed because it is integrated with the fuel pump unit.

• Mainly consists of a spring, release valve and diaphragm.

• Pressurizes fuel discharged by the fuel pump to approx. 390 kPa {3.98 kgf/cm2, 56.6 psi} with the spring, diaphragm and release valve, and then pumps it to the fuel distributor.

• If fuel pressure exceeds approx. 390 kPa {3.98 kgf/cm2, 56.6 psi}, the release valve opens to discharge unnecessary fuel pressure.