Fuel pump not working?

When you say the pump is working, do you mean you can hear it run when you turn the key on? If this is the case, we need to actually test the fuel pressure because I suspect the pump is running but not actually building pressure to send the fuel.

Let's run a fuel pressure test and see what we have and go from there.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

It is possible for the pump to run and not produce pressure. It could be the pump or a clogged fuel filter. The filter is in the fuel tank on this vehicle and part of the fuel pump assembly. (See pic 1.)

If there is no pressure making it to the engine fuel rail and there are no damaged fuel lines, chances are the pump is bad, but I would check the filter when the pump is out. Sadly, once you have everything out, it is a good idea just to replace the pump as well even if it is the filter because damage may have occurred to the pump leading to failure soon after. You don't want to remove it more than once.

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Here are a couple links you may find of interest. The first explains how the pump works and the second is a general description of how one is replaced.

https://www.2carpros.com/articles/how-a-fuel-pump-works

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

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Here are the directions for replacement specific to your vehicle. To do this requires removal of the fuel tank. I will start with those directions. The pump removal will be second.

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2006 Nissan-Datsun Truck Quest V6-3.5L (VQ35DE)
Fuel Tank Removal and Installation
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Tank Service and Repair Procedures Fuel Tank Removal and Installation
FUEL TANK REMOVAL AND INSTALLATION
FUEL TANK

pic 2

Removal and Installation

REMOVAL

WARNING:
Read "General Precautions" before working on the fuel system.
Refer to "General Precautions".

pic 3

1. Check the fuel level with the vehicle on a level surface. If the fuel gauge indicates more than the level as shown (7/8 full), drain the fuel from the fuel tank until the fuel gauge indicates a level at or below as shown (7/8 full).
- In case the fuel pump does not operate, use the following procedure.

a. Insert fuel tubing of less than 25 mm (0.98 in) diameter into the fuel filler tube through the fuel filler opening to drain fuel from the fuel filler tube.
b. Disconnect the fuel filler hose from the fuel filler tube.
c. Insert fuel tubing into the fuel tank through the fuel filler hose to drain fuel from the fuel tank.
-As a guide, the fuel level reaches or is less than the level on the fuel gauge as shown, when approximately 10 liters (2 5/8 US gal, 2 1/4 Imp gal) of fuel is drained from a full fuel tank.

2. Open the fuel filler lid and unscrew the fuel filler cap to release the pressure inside the fuel tank.
3. Release the fuel pressure from the fuel lines. Refer to "FUEL PRESSURE RELEASE".
4. Disconnect the negative battery terminal.
5. Remove the center exhaust tube, with mufflers.
6. Disconnect the parking brake cables from the equalizer, then disconnect the three parking brake cable mounting brackets on each cable and position the cables out of the way.
7. Remove the fuel tank protector.

pic 4

8. Disconnect the fuel filler hose, recirculation hose and EVAP canister hose at the fuel tank as shown.
9. Disconnect the fuel tank mounting straps while supporting the fuel tank.
10. Lower the fuel tank to access the top of the fuel level sensor unit, fuel filter, and fuel pump assembly.

pic 5

11. Disconnect the fuel level sensor unit, fuel filter, and fuel pump assembly electrical connector, and the fuel feed hose from the fuel level sensor unit, fuel filter, and fuel pump assembly.

pic 6

a. Disconnect the quick connectors as follows:
- Hold the sides of the connector, push in tabs and pull out the tube.
- If the connector and the tube are stuck together, push and pull several times until they start to move. Then disconnect them by pulling.

CAUTION:
- The tube can be removed when the tabs are completely depressed. Do not twist it more than necessary.
- Do not use any tools to remove the quick connector.
- Keep the resin tube away from heat. Be especially careful when welding near the tube.
- Prevent liquid acids, such as battery electrolyte, from getting on the resin tube.
- Do not bend or twist the tube during installation and removal.
- Only when the tube is replaced, remove the remaining retainer on the tube or fuel level sensor, fuel filter, and fuel pump assembly.
- When the tube or fuel level sensor, fuel filter, and fuel pump assembly is replaced, also replace the retainer with a new one (green colored retainer).

pic 7

- To keep the connecting portion clean and to avoid damage and foreign materials, cover them completely with plastic bags or something similar.

12. Remove the fuel tank.
13. If replacing the fuel tank, disconnect the EVAP hose and remove the fuel level sensor unit, fuel filter, and fuel pump assembly to transfer to the new fuel tank.

INSTALLATION
Installation is in the reverse order of removal.
- Before tightening the fuel tank mounting straps, temporarily install the fuel filler hose, recirculation hose, and EVAP canister hose. Tighten all fasteners to specification.
- Connect the quick connector as follows:
- Check the connection for damage or any foreign materials.

pic 8

- Align the connector with the tube, then insert the connector straight into the tube until a click is heard.
- After the tube is connected, make sure the connection is secure by pulling on the tube and the connector to make sure they are securely connected.

pic 9

- Visually confirm that the two retainer tabs are connected to the quick connector.
- Check the parking brake for proper operation. Adjust the parking brake as necessary.

INSPECTION AFTER INSTALLATION
Use the following procedure to check for fuel leaks:
1. Turn the ignition switch to ON (without starting the engine) to check the connections for fuel leaks with the electric fuel pump applying fuel pressure to the fuel piping.
2. Start the engine and let it idle to check that there are no fuel leaks at the fuel system tube and hose connections.

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2006 Nissan-Datsun Truck Quest V6-3.5L (VQ35DE)
Procedures
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Service and Repair Procedures
PROCEDURES
FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY

pic 10

Removal and Installation

REMOVAL

WARNING:
Read "General Precautions" before working on the fuel system.
Refer to "General Precautions".

1. Remove the fuel tank.

pic 11

2. Remove the lock ring using a socket drive handle and Tool as shown.
Tool number : KV991J0090 (J-46214)

pic 12

3. Remove the fuel level sensor, fuel filter, and fuel pump assembly from the fuel tank.

CAUTION: Do not bend the float arm during removal.

INSPECTION AFTER REMOVAL
Make sure the fuel level sensor, fuel filter, and fuel pump is free from defects and foreign materials.

INSTALLATION
Installation is in the reverse order of removal.

pic 13

- Install the fuel level sensor, fuel filter, and fuel pump assembly with the fuel feed hose facing the front of the vehicle.

pic 14

- Turn the lock ring until the lock ring is fully rotated into the fuel tank lock tabs as shown.

pic 15

- Connect the quick connector as follows:
- Check the connection for damage or any foreign materials.
- Align the connector with the tube, then insert the connector straight into the tube until a click is heard.
- After the tube is connected, make sure the connection is secure by pulling on the tube and the connector to make sure they are securely connected.

pic 16

- Visually confirm that the two retainer tabs are connected to the quick connector.

INSPECTION AFTER INSTALLATION
Use the following procedure to check for fuel leaks:
1. Turn the ignition switch to ON (without starting the engine) to check the connections for fuel leaks with the electric fuel pump applying fuel pressure to the fuel piping.
2. Start the engine and let it idle to check that there are no fuel leaks at the fuel system tube and hose connections.

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Let me know if this helps of if you have questions.

Take care,
Joe

Just because the pump runs doesn't mean it is building pressure. I would measure the pressure before going any further. If there is not pressure then there is no fuel. If the line is clear then the pump is the issue.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator