FUEL PUMP UNIT CONSTRUCTION/OPERATION [L8, LF, L3]

id0114b1101500

Structure

am6zzn00001768

Fuel flow

am6zzn00001769

1 | Fuel pump unit
2 | Fuel gauge sender unit
3 | Fuel pump
4 | Fuel filter (high-pressure)
5 | Fuel filter (low-pressure)
6 | Fuel reservoir cup
7 | Pressure regulator
8 | Fuel jet pump
9 | One-way valve
10 | Return fuel flow
11 | To fuel distributor
12 | Fuel tank

Fuel Pump Unit

• Mainly consists of a fuel filter (high-pressure), pressure regulator, fuel pump, fuel reserve cup, and fuel filter (low-pressure).
• A pressure regulator is built-in due to the adoption of a mechanical 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.
• 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 through the jet pump.
• 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 mechanical 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. 380 kPa {3.87 kgf/cm2, 55.1 psi} using the spring, diaphragm and release valve, and then pumps it to the fuel distributor.
• If fuel pressure exceeds approx. 380 kPa {3.87 kgf/cm2, 55.1 psi}, the release valve opens to discharge unnecessary fuel pressure.