Ignition Timing Check
WARNING: This page is about a different variant/trim than selected.
Required Special Tool:
MB991502: Scan Tool (MUT-II)
- Before inspection, set vehicles to the following conditions:
- Engine coolant temperature: 80 95°C (176 - 203°F)
- Lights and all accessories: OFF
- Transaxle: Neutral (P range on vehicles with A/T)
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "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 700 r/min.
- Select scan tool Mb991502 MFI 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:
- Is the MFI system diagnostic trouble code is output
- Timing belt cover and crankshaft position sensor installation conditions
- Crankshaft sensing blade condition
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. - 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 8° 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.