Curb Idle Speed Check

Required Special Tools: 

• MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
• MB992745: V.C.I.-Lite main harness A
• MB992747: V.C.I.-Lite USB cable short
• MB992748: V.C.I.-Lite USB cable long
• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicles Communication Interface (V.C.I.)
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

1. Before inspection, set the vehicle to the pre-inspection condition.
   CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
2. Turn the ignition switch to the "LOCK" (OFF) position and then connect scan tool (M.U.T.-III) to the data link connector. (Refer to DIAGNOSTIC FUNCTION ).
3. Set the timing light to the power supply line (terminal No. 3) of the ignition coil No. 2.
   NOTE: The power supply line is looped and also longer than the other ones.
4. Start the engine.
5. Run the engine at idle for 2 minutes.
6. Check that the actual ignition timing is at the standard value.

   Standard value: Approximately 10° BTDC 

   NOTE: The ignition timing fluctuates about ± 7°, even under normal operating condition.
   NOTE: It is automatically further advanced by about 5° from 10° Before Top Dead Center at higher altitudes.
   NOTE: Wait till approximately 1 minute passes after the engine started, and check the ignition timing when the engine stabilized.
7. Check the idle speed. Select item number 2 and take a reading of the idle speed.

   Curb idle speed: 600 ± 100 r/min 

   NOTE: The idle speed is controlled automatically by the idle air control system.
   Fig 1: Identifying Ignition Timing Pickup Loop

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. If the idle speed is outside the standard value. (Refer to SYMPTOM CHART ).
   CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
9. Turn the ignition switch to the "LOCK" (OFF) position and then disconnect the scan tool (M.U.T.-III).