GM Full Size Vans 1967-1986 Repair Guide

Diesel Injection Timing


See Figure 1

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Fig. Fig. 1: Diesel injection timing marks, 6.2L shown. Marks shown are in alignment

For the engine to be properly timed, the marks on the top of the engine front cover must be aligned with the marks on the injection pump flange. The engine must be OFF when the timing is reset.

On 49-state 6.2L engines, the marks are scribe lines. On California 6.2L engines, the marks are half circles.

  1. Loosen the three pump retaining nuts. If the marks are not aligned, adjustment is necessary.
  3. Loosen the three pump retaining nuts.
  5. Align the mark on the injection pump with the mark on the front cover. Tighten the nuts to 30 ft. lbs. (40 Nm).

Use a3/4in. (19.05mm) open end wrench on the nut at the front of the injection pump to aid in rotating the pump to align the marks.

  1. Adjust the throttle linkage if necessary.