Curb Idle Speed Check

Required Special Tool: 

MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V. C. I.
• MB991827: M.U.T.-III USB Cable
• MB991910: M.U.T.-III Main Harness A

1. Before inspection, set the vehicle in the following condition:
   • Engine coolant temperature: 80 - 95°C (176 - 203°F)
   • Lights and all accessories: OFF
   • Transaxle: Neutral (P range on vehicles with TC-SST)
     NOTE: On vehicles for Canada, the headlight, taillight, etc. remain lit even when the lighting switch is in "OFF" position but this is no problem for checks.
     CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
2. Connect scan tool MB991958 to the data link connector.
   Fig 1: Connecting Scan Tool MB991958 To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Set the timing light to the power supply line (terminal No. 4) of the ignition coil No. 1.
Fig 2: Identifying Ignition Coil, Equipment Side Connector And Power Supply Line
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Start the engine.
5. Run the engine at idle for 2 minutes.
6. Check the actual ignition timing is at the standard value.

   Standard value: Approximately 10° BTDC 

   NOTE: 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: 700 ± 100 r/min 

   NOTE: The idle speed is controlled automatically by the idle air control system.
8. If the idle speed is outside the standard value, refer to SYMPTOM CHART .
9. Remove the timing light.
   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
10. Disconnect scan tool MB991958 from the data link connector.