Jeep Wrangler/YJ 1987-1995 Repair Guide

Fuel Pump

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REMOVAL & INSTALLATION



See Figure 1



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Fig. Fig. 1: Common mechanical fuel pump

  1. Disconnect the inlet and outlet fuel lines, as well as any vacuum lines.
  2.  
  3. Remove the two fuel pump body attaching nuts and lockwashers.
  4.  
  5. Pull the pump and gasket (or O-ring) free of the engine. Make sure that the mating surfaces of the fuel pump and the engine are clean.
  6.  

To install:
  1. Cement a new gasket to the mounting flange of the fuel pump.
  2.  
  3. Position the fuel pump on the engine block so that the lever of the fuel pump rests on the fuel pump cam of the camshaft.
  4.  
  5. Secure the fuel pump to the block with the two cap screws and lock washers.
  6.  
  7. Connect the intake and outlet fuel lines to the fuel pump. Reattach the vacuum lines.
  8.  

TESTING



See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: Mechanical fuel pump pressure and capacity tests

Volume Check
  1. Disconnect the fuel line from the carburetor.
  2.  
  3. Place the open end in a suitable container.
  4.  
  5. Start the engine and operate it at normal idle speed. The pump should deliver at least one pint (16 oz.) in 30 seconds.
  6.  

Pressure Check
  1. Disconnect the fuel line at the carburetor.
  2.  
  3. Disconnect the fuel return line from the fuel filter, if so equipped, and plug the nipple on the filter.
  4.  
  5. Install a T-fitting on the open end of the fuel line and refit the line to the carburetor.
  6.  
  7. Plug a pressure gauge into the remaining opening of the T-fitting. The hose leading to the pressure gauge should not be any longer than 6 inches.
  8.  
  9. Start the engine and let it run at idle speed. Bleed any air out of the hose between the gauge and the T-fitting. On pumps with a fuel return line, the line must be plugged. Fuel pressure should be 3.00-5.00 psi (21-34 kPa) at idle.
  10.  

 
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