GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1996 🢒 GMC Suburban - 4WD 🢒 Engine 🢒 Engine Controls - 6.5L 🢒 Checking/Adjust Injection Timing

This procedure should be used after an injection pump installation or when injection timing needs to be checked or adjusted. A scan tool must be used to check or adjust injection timing. A static timing mark can be used as a reference. If a static timing mark is not present on the injection pump mounting flange, one can be scribed to further assist in how far the injection pump needs to be rotated.

Injection Pump Timing Specification
All injection pump timing averages 3.5°.

Important: There will be no change in engine performance or vehicle driveability if injection timing is advanced during the Time Set procedure. Injection timing must be set to Injection Timing Specifications. If injection timing is not set correctly, a possible DTC P0216 may set (see DTC P0216, Conditions for setting the DTC).

  1. Start engine.
  2. Engine at operating temperature.
  3. Install scan tool.
  4. Use scan tool to activate Time Set (if Time Set has been activated correctly, Des. Inj. Time on scan tool will read 0.0 degrees).

    5. Important: The Act. Inj. Time value on the scan tool will fluctuate. The Average reading should be 3.5 degrees.

  5. Act. Inj. Time (scan tool display) should be approximately 3.5 degrees. If not, continue to step 6.

    6. Important: If engine stalls during Time Set activation, slightly (1 mm equals 2 degrees) rotate the injection pump toward the driver side of the vehicle, tighten flange nuts and repeat Time Set.

  6. If the injection timing needs to be adjusted, continue. If not, adjustment is complete.

    7. Important: On 1997 models, move the A/C compressor to the side to improve access to the injection pump lower mounting bolts.

  7. Engine OFF, loosen injection pump flange nuts using J 41089.
  8. Slightly rotate injection pump using J 29872.
  9. Set Act. Inj. Time to 3.5°.

    10. Important: It is normal for Act. Inj. Time value on scan tool to fluctuate. Average fluctuation of Act. Inj. Time should be 3.5 degrees.

  10. Continue to repeat until average fluctuation of Act. Inj. time is 3.5°.
    11. • If Act. Inj Time is above 3.5 degrees SLIGHTLY (1 mm equals 2 degrees) ROTATE INJECTION PUMP TOWARDS THE PASSENGER SIDE OF VEHICLE.
    • If Act. Inj time is below 3.5 degrees, SLIGHTLY (1 mm equals 2 degrees) ROTATE INJECTION PUMP TOWARD DRIVERS SIDE OF VEHICLE.