Checking/Adjusting Injection Timing

1996 Chevrolet Tahoe 2D Utility, 6.5 SSECTION Checking/Adjusting Injection Timing

Original factory injection pump timing is marked with a static timing mark, a line scribed across both the pump mounting flange and the front cover. This static timing mark should be used as a reference. If timing mark is not present on mounting flange, scribe a line to assist in how far injection pump needs to be rotated.

  1. Start and warm engine to normal operating temperature. Connect Tech 1 scan tester. Set scan tester to OUTPUT TEST/INJ PUMP mode. Activate TDC TIME SET. The DESIRED INJ TIM value will read zero.
    NOTE: If engine stalls when TDC TIME SET is activated, turn engine off. Loosen injection pump nuts. Slightly rotate injection pump toward driver's side of vehicle. Tighten injection pump nuts. Repeat step 1).
  2. Ensure engine is running, then check "MEASURED INJ TIM" for proper timing specification. See DIESEL INJECTION PUMP TIMING table. If timing needs adjustment, turn engine off to avoid engine damage, then adjust injection pump. A 1-mm pump movement equals about 2 degrees timing.
DIESEL INJECTION PUMP TIMING (DEGREES BTDC @ RPM)

Application Man. Trans. Auto. Trans.
6.5L (VIN F, P & S) 3.5 @ Idle 3.5 @ Idle
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.