GM Full Size Vans 1987-1997 Repair Guide

Fuel Injection Pump

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REMOVAL & INSTALLATION



See Figures 1, 2 and 3



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Fig. Fig. 1: Accelerator cable linkage



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Fig. Fig. 2: Rotate the crankshaft so that the injection pump drive gear bolts become visible through the hole



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Fig. Fig. 3: Injection pump mounting

  1. Disconnect both batteries.
  2.  
  3. Remove the fan and fan shroud.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the fuel lines.
  8.  
  9. Disconnect the accelerator cable at the injection pump, and the detent cable (see illustration) where applicable.
  10.  
  11. Tag and disconnect the necessary wires and hoses at the injection pump.
  12.  
  13. Disconnect the fuel return line at the top of the injection pump.
  14.  
  15. Disconnect the fuel feed line at the injection pump.
  16.  
  17. Remove the air conditioning hose retainer bracket if equipped with A/C.
  18.  
  19. Remove the oil fill tube, including the crankcase depression valve vent hose assembly.
  20.  
  21. Remove the grommet for the oil filler tube.
  22.  
  23. Scribe or paint a matchmark on the front cover and on the injection pump flange.
  24.  
  25. The crankshaft must be rotated in order to gain access to the injection pump drive gear bolts through the oil filler neck hole.
  26.  
  27. Remove the injection pump-to-front cover attaching nuts. Remove the pump and cap all open lines and nozzles.
  28.  

To install:
  1. Replace the gasket.
  2.  
  3. Align the locating pin on the pump hub with the slot in the injection pump driven gear. At the same time, align the timing marks.
  4.  
  5. Attach the injection pump to the front cover, aligning the timing marks before tightening the nuts to 30 ft. lbs. (40 Nm).
  6.  
  7. Install the drive gear-to-injection pump bolts. Tighten the bolts to 20 ft. lbs. (25 Nm).
  8.  
  9. Install the remaining components as removed. Tighten the fuel feed line at the injection pump to 20 ft. lbs. (25 Nm). Start the engine and check for leaks.
  10.  

INJECTION TIMING ADJUSTMENT



See Figures 4, 5 and 6

Special tool J-26987, or its equivalent, will be necessary for this procedure.

For the engine to be properly timed, the lines on the top of the injection pump adapter and the flange of the injection pump must be aligned.

  1. The engine must be OFF for resetting the timing.
  2.  



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Fig. Fig. 4: Injection pump locating pin



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Fig. Fig. 5: Injection pump timing alignment marks



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Fig. Fig. 6: Slot in the injection pump

  1. Loosen the three pump retaining nuts with tool J-26987, an injection pump intake manifold wrench, or its equivalent.
  2.  
  3. Align the mark on the injection pump with the marks on the adapter and tighten the nuts. Tighten to 30 ft. lbs. (40 Nm). Use a 3 / 4 in. (19.05mm) open-end wrench on the boss at the front of the injection pump to aid in rotating the pump to align the marks.
  4.  
  5. Adjust the throttle rod.
  6.  

 
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