GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 41711 Injection Pump Wrench
    • J 29872-A Injection Pump Adjustment Tool

This procedure should be used after an injection pump installation or when the 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 determining how far the injection pump needs to be rotated.

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

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

  1. Start the engine.
  2. Allow the engine to idle at the normal operating temperature.
  3. Install the scan tool.
  4. Use the scan tool in order to activate the Time Set, if the Time Set has been activated correctly, Desired Injection Time on the scan tool will read 0.0 degree.
  5. Important: The actual injection Time value on the scan tool will fluctuate. The Average reading should be 3.5 degrees.

  6. The actual injection time, scan tool display, should be approximately 3.5 degrees. If not, continue to step 6.
  7. Important: If the engine stalls during the Time Set activation, slightly (1 mm equals 2 degrees) rotate the injection pump toward the driver side of the vehicle, tighten the flange nuts and repeat the Time Set.

  8. If the injection timing needs to be adjusted, continue. If not, this indicates that the adjustment is complete.

  9. Object Number: 707578  Size: SH
  10. With the engine OFF, use the J 41711 in order to loosen the left hand injection pump flange nut.

  11. Object Number: 706303  Size: SH
  12. With the engine OFF, use the J 41711 in order to loosen the right hand injection pump flange nut.
  13. With the engine OFF, use the J 41711 in order to loosen the center top injection pump flange nut.
  14. Use the J 29872-A in order to slightly rotate the injection pump.
  15. Set the actual injection time to 3.5 degrees.
  16. Important: It is normal for actual injection Time value on the scan tool to fluctuate. The average fluctuation of the actual injection Time should be 3.5 degrees.

  17. Continue to repeat until the average fluctuation of the actual injection time is 3.5 degrees.
  18. • If the actual injection time is above 3.5 degrees, slightly (1 mm equals 2 degrees) rotate the injection pump towards the passenger side of the vehicle.
    • If the actual Injection time is below 3.5 degrees, slightly (1 mm equals 2 degrees) rotate the injection pump toward the driver side of the vehicle.