Chrysler Full-Size Trucks 1989-1996 Repair Guide

Fuel Supply Pump

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REMOVAL & INSTALLATION



1989-93 Models

See Figures 1 and 2

The mechanical lift pump is located on the left side of the cylinder block. This design is operated by a lever which rides on an eccentric on the camshaft.



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Fig. Fig. 1: Cutaway view of the mechanical lift pump-1989-93 models

The pump housing has a weep hole at the bottom. If the diaphragm inside the pump ruptures, the weep hole will leak fuel and the pump must be replaced. The lift pump is not serviceable and must be replaced as a complete unit.



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Fig. Fig. 2: The manual lever on the pump must be in the UP position when the vehicle is operated-1989-93 models

On the pump is a manual lever meant to prime the fuel system and bleed air from the system if the vehicle has run out of fuel. During pump operation, the lever must be in the UP position.

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the low pressure fuel lines from the pump.
  4.  
  5. Remove the pump mounting screws, then remove the pump.
  6.  

To install:
  1. Clean the mating surface on the lift pump and engine block.
  2.  
  3. Use a new gasket and install the pump. Tighten the screws to 18 ft. lbs. (24 Nm).
  4.  
  5. Install the low pressure fuel lines.
  6.  
  7. Manually bleed the system of air.
  8.  
  9. Connect the negative battery cable.
  10.  

1994-96 Models

See Figures 3 and 4

The fuel transfer pump is located on the left side of the engine and above the starter motor.

  1. Disconnect both negative battery cables.
  2.  
  3. Remove the starter motor.
  4.  



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Fig. Fig. 3: Details of the fuel transfer pump mounting-1994-96 models

  1. Place a drain pan beneath the pump.
  2.  
  3. Remove the fuel line fittings at the top of both the fuel pump and fuel heater housing.
  4.  



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Fig. Fig. 4: Disconnect the fuel lines and the rubber hose, then unbolt and remove the fuel pump and heater housing as a unit-1994-96 models

  1. Remove the fuel hose clamps and rubber fuel hose.
  2.  
  3. Unfasten the mounting bolts, then remove the fuel pump and fuel heater assembly from the engine as one unit.
  4.  

To install:
  1. Clean the mating surfaces of the fuel heater mounting bracket, the fuel pump and the engine block of any gasket material.
  2.  
  3. Position the new gaskets, the fuel heater housing mounting bracket and the fuel pump to the engine.
  4.  
  5. Install the bolts, tightening them ALTERNATELY to 18 ft. lbs. (24 Nm).
  6.  


WARNING
As these bolts are tightened, the fuel pump plunger will be compressed. Tighten the fuel pump mounting bolts alternately to prevent damage to the fuel pump housing.

  1. Install the fuel line fittings to the pump and fuel heater, tightening them to 18 ft. lbs. (24 Nm).
  2.  
  3. Install the starter motor.
  4.  
  5. Connect the negative battery cables.
  6.  
  7. Bleed the fuel system of air.
  8.  

LOW PRESSURE BLEEDING



1989-93 Models

See Figure 5

  1. Place a drain pan under the separator filter.
  2.  
  3. Open the low pressure bleed screw.
  4.  



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Fig. Fig. 5: Turn the low pressure bleed screw and work the lever to purge the lines of air-1989-93 models

  1. Manual pump the lever on the fuel pump until the fuel exiting the bleed screw is free of air. If the manual lever feels as if it is not pumping, rotate (crank) the engine approximately 90°, then continue pumping as described.
  2.  
  3. Tighten the low pressure bleed screw to 6 ft. lbs. (8 Nm).
  4.  

1994-96 Models

See Figures 6 and 7



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Fig. Fig. 6: Location of the low pressure bleed bolt-1994-96 models

  1. Loosen the low pressure bleed bolt.
  2.  



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Fig. Fig. 7: Repeatedly press the rubber primer button to bleed the system of air-1994-96 models

  1. Operate the rubber push-button primer on the fuel transfer pump. Do this until the fuel exiting the bleed screw is free of air. If the primer button feels as if it is not pumping, rotate (crank) the engine approximately 90°, then continue pumping as described.
  2.  
  3. Tighten the low pressure bleed screw to 6 ft. lbs. (8 Nm).
  4.  

 
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