Overhaul

FUEL PUMP UNIT DISASSEMBLY/ASSEMBLY [MZR 1.5]

WARNING:
- Fuel line spills and leakage from the pressurized fuel system are dangerous. Fuel can ignite and cause serious injury or death, and damage to property and facilities. Fuel can also irritate the skin and eyes. To prevent this, do not damage the sealing surface of the fuel pump unit when removing or installing.

CAUTION:
- Be careful not to damage the O-ring or seal rubber. If it is damaged, a sealing malfunction might occur causing fuel leakage.
- Do not touch the fuel pump discharge pipe unless it is necessary. If servicing is needed, be careful not to damage the pipe with tools or other objects, or by applying lateral stress. If the pipe is damaged, it may cause fuel leakage or a fuel pump operation malfunction.
- Be careful not to damage the pressure regulator or fuel hose. If it is damaged, it may cause fuel leakage.
- When any parts are removed, make sure no foreign material has penetrated the part. Otherwise, it may cause a fuel pump unit operation malfunction.
- Protect any removed parts by placing them on rubber matting to prevent damage.
- Do not wear fabric gloves such as cotton gloves when servicing. Small pieces of fabric may get caught in the fuel pump or pressure regulator causing a fuel pump unit operation malfunction.
- When removing foreign material inside the reserve cup, use fuel for flushing. If pressurized air is used, the foreign material may penetrate into the reserve cup.
- Be careful not to damage the tab. If the tab is damaged, poor contact may occur resulting in fuel leakage.
- Do not apply a shock to the fuel pump. The magnet may be damaged if a shock is applied to the fuel pump.
- Be careful when handling the arm. If external forces are applied to the arm, it may deform and the plate may be damaged.

Fuel Pump Unit Structural View

Fuel Gauge Sender Unit Removal

1. Remove the fuel gauge sender unit wiring harness from the clip holder and two retaining slots and set it aside.

2. Remove the fuel gauge sender unit from the lower cover and set it aside.

3. Detach the tabs (4 locations) of the upper cover being careful not to damage them.

4. Remove the O-ring.

5. Disconnect the fuel gauge sender unit connector.

Pressure Regulator Removal

CAUTION:
- Performing the servicing with the fuel gauge sender unit secured could damage it. Always make sure the fuel gauge sender unit is able to move freely.

1. Remove the fuel gauge sender unit wiring harness from the clip holder and two retaining slots and set it aside.

2. Remove the fuel gauge sender unit from the lower cover and set it aside.

3. Remove the C-clip.

4. Remove the pressure regulator using pincers or a similar tool.

5. Remove the O-ring.

Fuel Pump Removal

CAUTION:
- Performing the servicing with the fuel gauge sender unit secured could damage it. Always make sure the fuel gauge sender unit is able to move freely.

1. Remove the fuel gauge sender unit wiring harness from the clip holder and two retaining slots and set it aside.

2. Remove the fuel gauge sender unit from the lower cover and set it aside.

3. Disconnect the fuel pump connector (fuel pump side).

4. Detach the tabs (4 locations) of the lower cover being careful not to damage them.

5. Pull out the fuel filter arm (high-pressure) and bend it as shown in the figure.

6. Remove the fuel pump and fuel filter (low-pressure) as a single component.

7. Remove the fuel pump from the fuel filter (low-pressure).

8. Remove the holding cover.

9. Remove the O-ring.

Fuel Filter (Low-pressure) Removal

CAUTION:
- Performing the servicing with the fuel gauge sender unit secured could damage it. Always make sure the fuel gauge sender unit is able to move freely.

1. Remove the fuel gauge sender unit wiring harness from the clip holder and two retaining slots and set it aside.

2. Remove the fuel gauge sender unit from the lower cover and set it aside.

3. Disconnect the fuel pump connector (fuel pump side).

4. Detach the tabs (4 locations) of the lower cover being careful not to damage them.

5. Pull out the fuel filter (high-pressure) arm and bend it as shown in the figure.

6. Detach the tabs (2 locations) of the lower cover being careful not to damage them.

7. Remove the fuel filter (low-pressure) being careful not to remove the fuel pump together with it.

Fuel Filter (High-pressure) Removal

CAUTION:
- Performing the servicing with the fuel gauge sender unit secured could damage it. Always make sure the fuel gauge sender unit is able to move freely.

1. Remove the fuel gauge sender unit wiring harness from the clip holder and two retaining slots and set it aside.

6. Using a precision screwdriver, disconnect the fuel filter (high-pressure) and the lower cover.

7. Remove the fuel pump and fuel filter (low-pressure) as a single component.

8. Remove the holding cover.

9. Remove the O-ring.

10. Remove the upper cover.

11. Remove the O-ring.

12. Disconnect the fuel gauge sender unit connector.

Fuel Gauge Sender Unit Installation

1. Connect the fuel gauge sender unit connector to the upper cover.

2. Looking from the side, verify that the fuel gauge sender unit connector is connected completely.

3. Apply clean oil to a new O-ring.

4. Install the O-ring to the upper cover.

5. Install the upper cover.

6. Verify that the upper cover tabs are securely installed.

7. Install the fuel gauge sender unit to lower cover.

8. Secure the fuel gauge sender unit wiring harness in the clip holder and two retaining slots.

Pressure Regulator Installation

1. Verify that two spacers and two O-rings are installed to the pressure regulator.

2. Apply clean oil to a new O-ring.

3. Install the pressure regulator.

4. Install the C-clip.

5. Install the fuel gauge sender unit to lower cover.

6. Secure the fuel gauge sender unit wiring harness in the clip holder and two retaining slots.

Fuel Pump, Fuel Filter (Low-pressure), Fuel Filter (High-pressure) Installation

1. Install using the following procedure.

When installing the fuel pump and fuel filter (high-pressure)
- Install the fuel pump and fuel filter (low-pressure) component to the fuel filter (high-pressure) with the fuel pump seal oriented as shown in the figure.

When installing the fuel filter (low-pressure)
- Install the fuel filter (low-pressure).

2. Verify that the fuel filter (low-pressure) tabs are securely installed.

3. Apply clean oil to a new O-ring.

4. Pull out the fuel filter arm (high-pressure) and bend it as shown in the figure.

5. Install the lower cover.

6. Verify that the lower cover tabs are securely installed.

7. Install the spring to the fuel filter arm (high-pressure) on the side with the spring installation mark. (See Fuel Pump Unit Structural View.)

8. Connect the fuel filter (high-pressure) arm.

9. Connect the fuel gauge sender unit connector and the fuel pump connector to the upper cover.

10. Looking from the side, verify that the fuel gauge sender unit connector and fuel pump connector (upper cover side) are connected completely.

11. Apply clean oil to a new O-ring.

12. Install the O-ring to upper cover.

13. Install the upper cover.

14. Verify that the upper cover tabs are securely installed.

15. Connect the fuel pump connector (fuel pump side).

16. Secure the fuel pump wiring harness in the clip holder.

17. Install the fuel gauge sender unit to the lower cover.

18. Secure the fuel gauge sender unit wiring harness in the clip holder and two retaining slots.