GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

DIESEL ENGINE INJECTION TIMING

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

This procedure requires the use of a Static Timing Gauge tool No. J-29763 or equivalent; DO NOT attempt any injection timing adjustments without this tool.

  1. Check that notched line on the injection pump flange is in alignment with notched line on the injection pump front bracket.
  2.  



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Fig. Fig. 1: Injection pump and flange alignment



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Fig. Fig. 2: Bring the No. 1 piston to TDC

  1. Bring the piston in No. 1 cylinder to top dead center on compression stroke by turning the crankshaft as necessary.
  2.  
  3. With the timing pulley housing cover removed, check that the timing belt is properly tensioned and that timing marks are aligned.
  4.  
  5. Disconnect the injection pipe(s) from the injection pump, then remove the distributor head screw and washer. Using the Static Timing Gauge tool No. J-29763 or equivalent, install it into the distributor head screw hole and set the lift to approximately 0.04 in. (1mm) from the plunger.
  6.  



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Fig. Fig. 3: Aligning the diesel engine timing marks



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Fig. Fig. 4: Removing the diesel engine distributor screw



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Fig. Fig. 5: Static timing gauge installation

  1. Use a wrench to retain the delivery holder when loosening the sleeve nuts on the injection pump side.
  2.  
  3. Bring the piston in No. 1 cylinder to a point 45-60° before top dead center (BTDC) by turning the crankshaft, then calibrate the dial indicator to zero.
  4.  



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Fig. Fig. 6: Bring the No. 1 piston to 45-60 degrees BTDC

  1. Turn the crankshaft pulley slightly in both directions and check that gauge indication is stable.
  2.  
  3. Turn the crankshaft in the normal direction of rotation, then record the reading of the dial indicator when the timing mark (15°) on the crankshaft pulley is in alignment with the pointer; the reading should be 0.020 in. (0.5mm).
  4.  



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Fig. Fig. 7: Turn the crankshaft in the normal direction of rotation to bring the No. 1 piston to 15 degrees BTDC

  1. If the reading of dial indicator deviates from the specified range, hold the crankshaft in position 15° BTDC and loosen two nuts on injection pump flange.
  2.  
  3. Move the injection pump to a point where dial indicator gives reading of 0.020 in. (0.5mm), then tighten pump flange nuts.
  4.  

 
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