Nissan Z - ZX 1970-1988 Repair Guide

Mechanical Fuel Pump

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See Figure 1



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Fig. Fig. 1: Disassembled mechanical fuel pump assembly


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

REMOVAL & INSTALLATION



1970-74 Models

The 260 Z is the only model covered by this guide that is equipped with both an electric fuel pump and a mechanical fuel pump.

  1. Disconnect the inlet and outlet lines from the pump.
  2.  
  3. Remove the mounting bolts.
  4.  
  5. Remove the pump and discard the gasket.
  6.  
  7. Lubricate the rocker arm, rocker arm pin and lever pin of the pump.
  8.  
  9. Put a new gasket into position and bolt the pump in place.
  10.  
  11. Connect the fuel lines.
  12.  

TESTING



  1. Disconnect the fuel pump-to-carburetor hose from the pump.
  2.  
  3. Tee in a pressure gauge as close to the carburetor as possible.
  4.  
  5. Start the engine and operate it at various speeds. The fuel pump pressure should be 3.4-4.25 psi (23-29 kPa).
  6.  

Pressure below these specifications indicates excessive wear, while high pressure indicates a faulty spring or diaphragm. In either case, the pump requires removal and disassembly for replacement of faulty parts. If the pump passes the pressure test but if there is still a question that it's performance may not be adequate, proceed with the capacity test below.

  1. Disconnect the pressure gauge from the tee and position a large container under the open end.
  2.  
  3. Start the engine and operate it at 1,000 rpm for 15 seconds. The pump should deliver at least 0.42 qts. (400cc) of fuel in this time.
  4.  

Failure of this test indicates a faulty pump or clogged suction line.

 
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