GM Service Manual Online
For 1990-2009 cars only

Setting Timing for Chevrolet Tahoe - 2WD 1997

Camshaft Retard Offset Test

The ignition timing cannot be adjusted. The distributor may need adjusting to prevent crossfire. To insure proper alignment of the distributor, perform the following:

  1. With the ignition OFF, install a scan tool to the DLC.
  2. Start the engine and bring to normal operating temperature.
  3. Important: Cam Retard Offset reading will not be accurate below 1000 RPM

  4. Increase engine speed to 1000 RPM.
  5. Monitor the Cam Retard Offset.
  6. If the Cam Retard indicates a value of 0° ± 2°, the distributor is properly adjusted.
  7. If the Cam Retard does not indicate 0° ± 2°, the distributor must be adjusted.

Adjusting Camshaft Retard Offset


Object Number: 18446  Size: SH
  1. With the engine OFF, slightly loosen the distributor hold down bolt.
  2. Important: Cam Retard Offset reading will not be accurate below 1000 RPM

  3. Start the engine and raise engine speed to 1000 RPM.
  4. Using a scan tool monitor Cam Retard Offset.
  5. Rotate the distributor as follows:
  6. 4.1. To compensate for a negative reading, rotate the distributor in the counterclockwise direction.
    4.2. To compensate for a positive reading, rotate the distributor in the clockwise direction.
  7. Repeat step 4 until 0° ±2° is obtained.
  8. Turn the ignition OFF.
  9. Tighten the distributor hold-down bolt to 3N·m(25 lb. ft.).
  10. Start the engine, raise engine speed to 1000 RPM and recheck Camshaft Retard Offset.