Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Mechanical Fuel Pump

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See Figure 1



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Fig. Fig. 1: Cutaway view of a mechanical type fuel pump-1982-87 vehicles

OPERATION



The fuel pump is a mechanically operated, diaphragm type driven by the fuel pump eccentric on the camshaft. The pump is located on the lower right side of the engine.

The pump cannot be disassembled. If it fails either the pressure or the volume test, replace the unit.

REMOVAL & INSTALLATION




CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

  1. Disconnect the fuel lines from the fuel pump.
  2.  

Be sure to plug the line leading from the fuel tank to prevent the excess loss of fuel.

  1. Remove the two fuel pump mounting nuts and the fuel pump assembly from the right side of the engine.
  2.  

To install:
  1. Clean gasket mating surfaces.
  2.  
  3. Use a new gasket and/or sealant and mount the pump to the engine block. Torque the fuel pump bolts to 84-108 inch lbs. (10-13 Nm).
  4.  
  5. Connect the fuel lines to the fuel pump.
  6.  
  7. Start the engine and check for fuel leaks.
  8.  

TESTING



Static Pressure

CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

  1. Disconnect the fuel line at the carburetor. Using a T-connector, attach two rubber hoses to the connector, then install it between the fuel line and the carburetor fitting.
  2.  

When disconnecting the fuel line, be sure to place a container under the line to catch the excess fuel in the line.

  1. Connect a fuel pump pressure gauge to the T-connector and secure it with a clamp.
  2.  
  3. Start the engine and check the pressure at various speeds. The pressure should be 3.0-3.8 psi (20.7-26.2 kPa) for 1982-83 or 2.8-3.8 psi (19.3-26.2 kPa) for 1984 and later. There is usually enough gasoline in the float bowl to perform this test.
  4.  
  5. If the pressure is okay, perform a capacity test. Remove the gauge and the T-connector assembly, then reinstall the fuel line to the carburetor.
  6.  

Capacity
  1. Disconnect the fuel line from the carburetor and place the line in a graduated container.
  2.  


WARNING
Do NOT use a glass or styrofoam container when checking fuel pump volume.

  1. Fill the carburetor float bowl with gas.
  2.  
  3. Start the engine and run it for one minute at about 600 rpm. The pump should deliver 44.0 oz. (1300 ml) per minute.
  4.  

 
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