Jeep CJ/Scrambler 1971-1986 Repair Guide

Fuel Pump

Print

See Figures 1, 2, 3, 4, 5, 6 and 7

REMOVAL & INSTALLATION



  1. For some engines (such as the 304 V8) it will be necessary to remove the power steering pump and the AIR pump for access to the fuel pump assembly.
  2.  
  3. Disconnect the inlet and outlet fuel lines, and any vacuum lines.
  4.  
  5. Remove the two fuel pump body attaching nuts and lockwashers.
  6.  
  7. 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.
  8.  
  9. Cement a new gasket to the mounting flange of the fuel pump.
  10.  
  11. 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.
  12.  
  13. Secure the fuel pump to the block with the two cap screws and lock washers.
  14.  
  15. Connect the intake and outlet fuel lines to the fuel pump, and any vacuum lines.
  16.  



Click image to see an enlarged view

Fig. Fig. 1: Loosen the fuel pump mounting bolts



Click image to see an enlarged view

Fig. Fig. 2: Then remove the fuel lines from the pump, make sure you use a backup wrench



Click image to see an enlarged view

Fig. Fig. 3: Remove the fuel pump mounting bolts



Click image to see an enlarged view

Fig. Fig. 4: Remove the fuel pump from the vehicle



Click image to see an enlarged view

Fig. Fig. 5: Exploded view of the fuel pump used on the 4-134 engine



Click image to see an enlarged view

Fig. Fig. 6: Exploded view of the combined fuel and vacuum pump used on some 4-134 engines



Click image to see an enlarged view

Fig. Fig. 7: Cutaway view of the fuel pump used on 4-151, 6-232, 6-258, 8-304 and 1984-86 4-150 engines

FUEL PUMP TESTING



See Figure 8

Volume Check

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

Disconnect the fuel line at the carburetor. Disconnect the fuel return line from the fuel filter if so equipped, and plug the nipple on the filter. Install a T-fitting on the open end of the fuel line and refit the line to the carburetor. 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. 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. Start the engine. Fuel pressures are as follows:



4-134: 2.50-3.75psi @ 1,800 rpm
 
4-150: 4.00-5.00psi @ idle
 
4-151: 6.50-8.00psi @ idle
 
6-225: 3.75psi minimum @ 600 rpm
 
6-232: 3.00-5.00psi @ idle
 
6-258: 3.00-5.00psi @ idle
 
8-304: 4.00-6.00psi @ idle
 



Click image to see an enlarged view

Fig. Fig. 8: Checking the fuel pump pressure and volume at the carburetor

 
label.common.footer.alt.autozoneLogo