GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 1997 🢒 Isuzu - N Series 🢒 Engine 🢒 Engine Controls - 5.0L, 5.7L, and 7.4L 🢒 Distributor Overhaul

Disassembly Procedure
  1. Turn OFF the ignition.

    2. Notice: The ignition system distributor driven gear and rotor may be installed in multiple positions. In order to avoid mistakes, mark the distributor on the following components in order to ensure the same mounting position upon reassembly:

       • The distributor driven gear
       • The distributor shaft
       • The rotor holes
    Installing the driven gear 180 degrees out of alignment, or locating the rotor in the wrong holes, will cause a no-start condition. Premature engine wear or damage may result.

  2. Remove the distributor. Refer to Distributor Replacement .

    3. Object Number: 301396 Size: SH
  3. Remove the screws from the rotor.
  4. Remove the rotor.

    5. Object Number: 156752 Size: SH
  5. Note the locating holes that the rotor was removed from:
    6. • The rotor screw holes (1)
    • The rotor locator pin holes (2)

    Object Number: 301398 Size: SH
  6. Line up the square-cut hole in the vane wheel with the CMP sensor.

    7. Object Number: 156754 Size: SH
  7. Remove and discard the screws retaining the camshaft position (CMP) sensor.

    8. Object Number: 746441 Size: SH
  8. Remove the CMP sensor.
  9. Note the dimple located below the roll pin hole on one side of the gear. The dimple will be used to properly orient the gear onto the shaft during reassembly.

    10. Object Number: 301198 Size: SH

    Caution: Wear safety glasses in order to avoid eye damage.

  10. Support the distributor drive gear in a V-block or a similar fixture.
  11. Drive out the roll pin with a suitable punch.

    12. Object Number: 301405 Size: SH
  12. Remove the driven gear from the distributor shaft.
  13. Remove the round washer.
  14. Remove the tang washer.
  15. Remove the shim washer (1).

    16. Object Number: 301419 Size: SH
  16. Remove the old oil seal gasket.

Assembly Procedure

    Object Number: 156754 Size: SH

    Important: Installing the driven gear 180 degrees out of alignment, or locating the rotor in the wrong holes, will cause a no-start condition. Premature engine wear or damage may result.

  1. Line up the square-cut hole in the vane wheel for the camshaft position (CMP) sensor.

    2. Object Number: 156755 Size: SH
  2. Insert the sensor into the housing.

    3. Object Number: 4341 Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  3. Install new screws for the camshaft position (CMP) sensor.

    4. Tighten
    Tighten the screws to 2.2 N·m (20 lb in).


    Object Number: 156752 Size: SH
  4. Identify the correct rotor mounting position:
    5. • At the rotor screw holes (1)
    • At the rotor locator pin holes (2)

    Object Number: 301396 Size: SH
  5. Install the distributor rotor according to the index marks.
  6. Install the screws that retain the rotor .

    7. Tighten

        • Tighten the NEW screws to 2.2 N·m (20 lb in).
        • Tighten the USED screws to 1.9 N·m (17 lb in).

    Object Number: 301405 Size: SH
  7. Install the shim washer (1) on the bottom of the distributor shaft.
  8. Install the tang washer.
  9. Install the round washer.
  10. Install the driven gear according to the index marks.

    11. Object Number: 301395 Size: SH
  11. Install the gear and align the white paint mark on the bottom stem of the distributor and the pre-drilled indent hole in the bottom of the gear (3).
  12. Determine if the driven gear is installed incorrectly. The dimple will be approximately 180 degrees opposite the rotor segment when installed in the distributor.

    13. Object Number: 301198 Size: SH

    Caution: Wear safety glasses in order to avoid eye damage.

  13. Support the distributor drive gear in a V-block or a similar fixture.
  14. Install the roll pin with a suitable punch and hammer in order to hold the driven gear in the correct position.

    15. Object Number: 320250 Size: SH
  15. Install the distributor cap.
  16. Install new distributor cap screws.

    17. Tighten
    Tighten the screws to 2.4 N·m (21 lb in).


    Object Number: 301419 Size: SH
  17. Install the new oil seal gasket under the mounting flange of the distributor base.
  18. Install the distributor. Refer to Distributor Replacement .
  19. Install the electrical connector to the distributor.
  20. Install the spark plug wires to the distributor cap.

    21. Important: The ignition coil wire must not touch anything. Rubbing will ground or short the wire after a short time.

  21. Install the ignition coil wire.