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

Diesel Injection Pump Timing

Print

CHECKING & ADJUSTMENT



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

The following procedure requires the use of the Static Timing Gauge tool No. J-29763 or equivalent.

  1. Check that the notched line on the injection pump flange is in alignment with the notched line on the injection pump front bracket.
  2.  
  3. Position the No. 1 piston on TDC of the compression stroke by turning the crankshaft as necessary.
  4.  

Make sure No. 1 cylinder is on the compression stroke; it is possible to align the timing marks incorrectly.

  1. Remove the upper fan shroud, if not already done.
  2.  
  3. With the upper cover removed, check that the timing belt is properly tensioned and that the timing marks are properly aligned. If the marks are not aligned properly, the timing belt will have to be removed and readjusted.
  4.  
  5. With the injection lines removed, remove the distributor head screws and washer from the injection pump.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Injection pump and flange alignment



Click image to see an enlarged view

Fig. Fig. 2: No. 1 piston at TDC



Click image to see an enlarged view

Fig. Fig. 3: Location of the distributor head screw (arrow) that must be removed in order to install the dial gauge

  1. Install the Static Timing Gauge tool No. J-29763 or equivalent, and set the lift to approximately 0.04 in. (1mm) from the plunger.
  2.  
  3. Position the piston of the No. 1 cylinder to a point 45-60° BTDC by turning the crankshaft, then calibrate the dial indicator to 0°. Turn the crankshaft pulley slightly in both directions and check that the gauge indication is stable.
  4.  
  5. Turn the crankshaft in the normal direction of rotation and record the reading of the dial indicator when the timing mark (15°) on the crankshaft pulley is in alignment with the TDC pointer. The dial indicator should read 0.020 in. (0.5mm).
  6.  



Click image to see an enlarged view

Fig. Fig. 4: Injection timing dial gauge installed in injection pump



Click image to see an enlarged view

Fig. Fig. 5: Before adjusting the injection timing, bring the No. 1 piston 45-60 degrees BTDC and then zero the dial gauge



Click image to see an enlarged view

Fig. Fig. 6: Location of the injection pump flange and bracket bolts

  1. If the reading on the dial indicator is not as described, hold the crankshaft in position (15°) before TDC and loosen two nuts on the injection pump flange. Move the injection pump to a point where the dial indicator gives a reading of 0.020 in. (0.5mm), then tighten the pump flange nuts.
  2.  
  3. Recheck the dial indicator reading and readjust the injection pump as necessary. Remove the dial indicator from the pump.
  4.  
  5. Install the distributor screw and washer into the injection pump, then tighten.
  6.  
  7. Install the injection lines; DO NOT overtighten the connections.
  8.  
  9. To complete the installation, reverse the removal procedures. Adjust the idle speed and the fast idle speed as described in Engine Electrical of this repair guide. Check for leaks in the fuel system and correct, if necessary.
  10.  

 
label.common.footer.alt.autozoneLogo