Chevrolet Chevette/1000 1976-1988 Repair Guide

Injection Pump

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REMOVAL & INSTALLATION





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Fig. Fig. 1Exploded view of the diesel injection pump linkage. Note the location of the idle adjusting screw and the fast idle adjuster (knurled nut)



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Fig. Fig. 2The tension spring is located behind the front plate beside the injection pump on the diesel engine



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Fig. Fig. 3Use a lockbolt to ensure the index marks on the injection pump gear and the front plate stay in alignment

This procedure will require the use of two special tools: a gear puller (J-22888) and a fixing plate (J-29761). It is a long and complicated procedure and must be performed in conjunction with the following injection timing procedure. We do not suggest that the average amateur mechanic perform these procedures.

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system. Remove the fan shroud, radiator and coolant recovery tank.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the bypass hose leading from the front cover and then remove the upper half of the front cover.
  2.  

Fan removal may facilitate better access to certain front cover retaining bolts.

  1. Loosen the timing belt tension pulley and plate bolts. Slide the tensioner over.
  2.  
  3. Unscrew the two retaining bolts and remove tension spring from behind the front plate, by the injection pump.
  4.  
  5. Remove the injection pump gear retaining nut and then remove the gear with a gear puller.
  6.  
  7. Tag and disconnect any wires, hoses or cables leading from the pump. Disconnect and plug the fuel feed lines.
  8.  
  9. Remove the fuel filter. Disconnect the injector lines at the pump and at the injector nozzles and remove the lines.
  10.  
  11. Unscrew the four retaining bolts and remove the pump rear bracket.
  12.  
  13. Unscrew the nuts attaching the pump flange to the front plate and then remove the pump complete with the fast idle device and return spring.
  14.  

To install:

  1. Place the pump in position and tighten the flange bolts. Position the rear bracket and tighten the bracket-to-pump bolts. There should be no clearance between the rear bracket and pump bracket.
  2.  
  3. Reconnect all wires, hoses and cable.
  4.  
  5. Slide the pump gear onto its shaft, making sure that it is aligned with the key groove. Turn the gear until the notch mark aligns with the index mark on the front plate. Thread a lockbolt (8mmX1.25) through the gear and into the front plate and then tighten the retaining nut to 45 ft. lbs.
  6.  
  7. Remove the cylinder head cover. Position the No. 1 piston at TDC of the compression stroke and install the fixing plate into the slot in the rear of the camshaft to prevent it from rotating.
  8.  
  9. Unscrew the cam gear retaining bolt and, using a puller, remove the gear. Reinstall the gear loosely so that it can be turned smoothly by hand.
  10.  
  11. Grasp the timing belt on each side near the lower half of the front cover; move it back and forth until the cogs on the belt engage with those on the lower gears. Slide the belt over the pump gear and then over the cam gear (you may need to turn the cam gear slightly to facilitate proper engagement of the cogs).
  12.  
  13. Make sure that any slack in the belt is concentrated around the tension pulley and NOT around or between the two upper gears. Depress the tension pulley with your finger and then install the tension spring.
  14.  
  15. Partially tighten the tension pulley bolts; first the upper, then the lower. Tighten the cam gear retaining bolt to 45 ft. lbs.
  16.  
  17. Remove the pump gear lockbolt. Remove the fixing plate from the end of the camshaft.
  18.  
  19. Check that the No. 1 piston is still at TDC. Check that the marks on the front plate and the pump gear are still aligned. Check that the fixing plate still fits properly into the rear of the camshaft.
  20.  


WARNING
If these three steps do not check out correctly, repeat the entire procedure. DO NOT attempt to compensate by moving the camshaft, pump gear or crankshaft.

  1. Loosen the tension pulley and plate bolts. Make sure the belt slack is concentrated around the pulley and then tighten the bolts in the same manner as before. Belt tension should be checked at a point between the cam gear and the pump gear.
  2.  
  3. Installation of the remaining components is in the reverse order of removal.
  4.  
  5. Check the injection timing.
  6.  

 
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