Ignition Timing Check
Required Special Tool:
MB991502: Scan Tool (MUT-II)
- Before inspection, set vehicles in the following condition:
- Engine coolant temperature: 80 - 95°C (176 - 203°F)
- Lights and all accessories: OFF
- Transmission: P range
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502. - Connect scan tool MB991502 to the data link connector.
- Set up a timing light.
- Start the engine and run it at idle.
- Check that the idle speed is approximately 750 RPM.
- Select scan tool MB991502 actuator test "ITEM NUMBER 17".
- Check that basic ignition timing is within the standard value.
Standard value: 5° BTDC +/- 3°
- If the basic ignition timing is not within the standard value, check the following items:
- Diagnosis Output
- Timing Belt Cover And Crankshaft Position Sensor Installation Conditions
- Crankshaft Sensing Blade Condition
- Press the clear key on scan tool MB991502 (select forced drive stop mode), and cancel the actuator test.
- Check that the actual ignition timing is at the standard value.
Standard value: Approximately 10° BTDC
NOTE: Ignition timing fluctuates about +/- 7° Before Top Dead Center, even under normal operating condition.NOTE: It is automatically further advanced by about 5° to 10° Before Top Dead Center at higher altitudes.
CAUTION:
If the actuator test is not canceled, the forced drive will continue for 27 minutes. Driving in this state could lead to engine failure.