1989 Mitsubishi Sigma AutomaticFACTORY OEM SERVICE PROCEDURE

Idle Speed & Ignition Timing

NOTE: If engine is equipped with a dual diaphragm distributor, vehicle will not have an ignition timing adjustment connector.
  1. Ensure vehicle is at operating temperature, all accessories are off and transmission is in Park or Neutral. Vehicle front wheels must be in straight-ahead position and curb idle speed set to specification. If vehicle is equipped with a dual diaphragm distributor, go to next step. If vehicle is equipped with an ignition timing adjustment connector, go to step 3).
  2. Disconnect vacuum hose farthest from distributor. Plug vacuum hose. Check basic ignition timing. Connect vacuum hose to distributor. Check actual ignition timing. Refer to the IGNITION TIMING  table.
  3. Ground ignition timing adjustment connector. Refer to IGNITION TIMING ADJUSTMENT CONNECTOR LOCATION  table. Check basic ignition timing. Disconnect ground wire on ignition timing adjustment connector. Check actual ignition timing. Refer to the IGNITION TIMING  table.
    IGNITION TIMING (Degrees BTDC @ RPM)

    Application (1) Basic (2)(3) Actual
    1.5L
    Precis
    Federal 5 @ 650-850 N/A
    California 3 @ 650-850 N/A
    Mirage 5 @ 650-850 15 @ 650-850
    1.6L Mirage 5 @ 650-850 8 @ 650-850
    2.0L Galant & Pickup 5 @ 600-800 (4) 10 @ 600-800
    2.4L Van/Wagon 5 @ 650-850 8 @ 650-850
    2.6L
    Starion 10 @ 750-950 15 @ 750-950
    Montero & Pickup 7 @ 750-950 12 @ 750-950
    3.0L Montero & Sigma 5 @ 600-800 15 @ 600-800
    (1) With ignition timing adjustment connector grounded or vacuum hose (farthest from dist.) disconnected.
    (2) With ignition timing adjustment connector ungrounded or vacuum hose (farthest from dist.) connected. Ignition timing may fluctuate.
    (3) If altitude is more than 2300 ft. above sea level, actual timing may be advanced.
    (4) Actual ignition timing on Galant Dual Overhead Camshaft (DOHC) engine is 12 degrees.
    IGNITION TIMING ADJUSTMENT CONNECTOR LOCATION (1)

    Application (2) Wire Color Location
    Starion Red/Yellow Right front of engine compartment
    Galant White/Yellow Left rear of engine compartment
    Mirage Yellow/Red Middle of firewall
    Montero White/Yellow Left rear of engine compartment
    Sigma Black/Blue Front of left shock tower
    Van/Wagon Silver Rear center of engine compartment
    (1) Remove waterproof female connector (if equipped) for access to wire.
    (2) This wire in connector is grounded for basic timing adjustment.
Factory Service Tools

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When to See a Mechanic

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

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

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