Air/Fuel Mixture: Testing and Inspection
IDLE MIXTURE 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 MB9911958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB9911958.
2. Connect scan tool MB991958 to the data link connector.
3. Set the timing light to the power supply line (terminal No. 1) of the ignition coil No. 1.
NOTE: The power supply line is looped and also longer than other ones.
4. Start the engine and increase the engine speed to 2,000 - 3,000 r/min for 2 minutes.
5. Check that the actual ignition timing is within the standard value.
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.
6. Set the CO, HC tester.
7. Check the CO contents and the HC contents at idle.
Standard value:
CO contents: 0.5 % or less
HC contents: 100 ppm or less
8. If the CO and HC contents do not remain inside the standard value, inspect the MFI system. (Refer to Multiport Fuel Injection (MFI) [2AL Engine] -Multiport Fuel Injection (MFI) Diagnosis -Symptom Chart.) Symptom Chart
9. Remove the CO, HC tester and the timing light.
10. Turn the ignition switch to the "LOCK" (OFF) position and disconnect the scan tool MB 991958.