Idle Speed: Testing and Inspection
CURB IDLE SPEED CHECKRequired 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 degrees C (176 - 203 degrees F)
^ Lights, and all accessories: OFF
^ Transaxle: P range
NOTE: 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 "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
2. Connect scan tool MB991958 to the data link connector.
3. Set the timing light to the power supply line (terminal No. 3) of the ignition coil No. 4.
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 the actual ignition timing.
Standard value: Approximately 10 degrees BTDC
NOTE: Ignition timing fluctuates about ± 7 degrees , even under normal operating condition.
NOTE: It is automatically further advanced by about 5 degrees from 10 degrees 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: 680 ± 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 Multiport Fuel Injection (MFI) - Multiport Fuel Injection (MFI) Diagnosis - Symptom Chart Symptom Chart.
9. Remove the timing light.
10. Turn the ignition switch to the "LOCK" (OFF) position and then disconnect the scan tool MB991958 from data link connector.