1990 Mitsubishi Precis Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Idle Speed & Ignition Timing

  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 ignition basic timing. Connect vacuum hose to distributor. Check ignition actual timing. Refer to IGNITION TIMING  table in this article.
  3. Ground ignition timing adjustment connector. Timing adjustment connector is a Yellow/Red wire at left of center, on firewall. Check ignition basic timing.
  4. Disconnect ground wire on ignition timing adjustment connector. Check ignition actual timing. Refer to IGNITION TIMING  table.
    IDLE SPEED & CO LEVEL SPECIFICATIONS (1)

    Application Idle RPM CO %
    Montero (2.6L) 700-900 .1-.3
    (1) Idle speed and mixture are computer controlled on fuel injected models.
    IGNITION TIMING (Degrees BTDC @ RPM)

    Application (1) Basic (2)(3) Actual
    1.5L
    Mirage 5 @ 600-800 10 @ 600-800
    Precis 5 @ 600-800 10 @ 600-800
    1.6L
    Mirage 5 @ 650-850 8 @ 650-850
    1.8L
    Eclipse 5 @ 600-800 10 @ 600-800
    2.0L
    Eclipse & Galant (VIN R) 5 @ 650-850 8 @ 650-850
    Galant (VIN V) 5 @ 650-850 10 @ 650-850
    2.4L
    Pickup & Van/Wagon 5 @ 650-850 8 @ 650-850
    2.6L
    Montero 7 @ 750-950 12 @ 750-950
    3.0L
    Montero & Sigma 5 @ 600-800 15 @ 600-800
    Pickup 8 @ 600-800 15 @ 600-800
    (1) With ignition timing adjustment connector grounded or vacuum hose (farthest from distributor) disconnected.
    (2) With ignition timing adjustment connector ungrounded or vacuum hose (farthest from distributor) connected. Ignition timing may fluctuate.
    (3) If vehicle altitude is more than 2300 ft. above sea level, actual timing may be advanced.
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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