AMC Coupes/Sedans/Wagons 1975-1988 Repair Information

Fuel Pump

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REMOVAL & INSTALLATION



See Figures 1 through 7

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Fig. Fig. 1: Common fuel pump assembly used on all models except the 4-151 engines



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Fig. Fig. 2: Exploded view of the fuel pump components4-151 engine



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Fig. Fig. 3: Use a pair of pliers to disengage the spring type fuel return line clamp ...



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Fig. Fig. 4: ... then separate the hose from the fuel pump



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Fig. Fig. 5: Use a flare nut wrench to loosen the inlet line nut ...



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Fig. Fig. 6: ... then gently pull the line from the fuel pump being careful not to bend or kink it



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Fig. Fig. 7: Use an extension to reach the fuel pump retaining bolts

  1. Disconnect the inlet and outlet fuel lines, and 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, and any vacuum lines.
  8.  


WARNING
When installing the 4-121 engine fuel pump, be sure that the pushrod is positioned properly against the actuating lever or the pump may be damaged when the screws are tightened.

TESTING - Volume Check



See Figure 8

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Fig. Fig. 8: Connect a fuel pressure gauge as shown to check pump volume and pressure

Disconnect the fuel line from the carburetor. Place the open end in a suitable container. Start the engine and operate it at normal idle speed. The pump should deliver at least one pint in 30 seconds.

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.
  8.  
  9. The hose leading to the pressure gauge should not be any longer than 6 in. (152.5mm).
  10.  
  11. Start the engine and let it run at idle speed.
  12.  
  13. Bleed any air out of the hose between the gauge and the T-fitting.
  14.  
  15. On pumps with a fuel return line, the line must be plugged.
  16.  

  1. Start the engine. Fuel pressures are as follows:4-121 Engine: 4.00-6.00psi @ idle4-150 Engine: 4.00-5.00psi @ idle4-151 Engine: 6.50-8.00psi @ idle6-232 Engine: 3.00-5.00psi @ idle6-258 Engine: 3.00-5.00psi @ idle8-304 Engine: 4.00-6.00psi @ idle8-360 Engine: 4.00-6.00psi @ idle8-401 Engine: 4.00-6.00psi @ idle
  2.  

 
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