Jeep CJ 1945-1970 Repair Information

Fuel Pump

Print

TESTING



See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Set up a container, pressure gauge and fuel lines as shown for the pressure and volume tests

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 1 pt. (0.473L) 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 tee 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 tee fitting. The hose leading to the pressure gauge should not be any longer than 6 in. (15cm). Start the engine and let it run at idle speed. Bleed any air out of the hose between the gauge and the tee fitting. On pumps with a fuel return line, the line must be plugged. Start the engine. Fuel pressures are as follows:



4-134 engine-2.50-3.75 psi (17.24-25.85 kPa) @ 1,800 rpm
 
6-225 engine-3.75 psi (25.85 kPa) minimum @ 600 rpm
 
6-226 engine-3.50-5.50 psi (24.13-37.92 kPa) @ 1,800 rpm
 
6-230 engine-3.50-5.50 psi (24.13-37.92 kPa) @ 600 rpm
 

REMOVAL & INSTALLATION



See Figures 2, 3, 4 and 5

All Engines
  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.  
  7. Cement a new gasket to the mounting flange of the fuel pump.
  8.  
  9. 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.
  10.  
  11. Secure the fuel pump to the block with the two cap screws and lock washers.
  12.  
  13. Connect the intake and outlet fuel lines to the fuel pump, and any vacuum lines.
  14.  



Click image to see an enlarged view

Fig. Fig. 2: Cross-section view of the internal workings of the screen-type filter fuel pump used on early L-head 4-134 engines



Click image to see an enlarged view

Fig. Fig. 3: Exploded view of the paper element-type filter fuel pump used on late L-head 4-134 engines



Click image to see an enlarged view

Fig. Fig. 4: Exploded view of the screen-type filter fuel pump used on early L-head 4-134 engines



Click image to see an enlarged view

Fig. Fig. 5: Exploded view of the fuel pump used on F-head 4-134 and 6-230 engines

 
label.common.footer.alt.autozoneLogo