Idle Mixture Check - Mitsubishi Electric Lancer Evolution-VII Workshop Manual

11A-10
ENGINE - ENGINE -
On-vehicle Service On-vehicle Service
Standard value: 5_ BTDC ± 3_
5. Run the engine at idle for 2 minutes.
6. Check the idle speed. Select item No. 22 and take a
reading of the idle speed.
Curb idle speed: 850 ± 100 r/min
NOTE
The idle speed is controlled automatically by the idle speed
control (ISC) system.
7. If the idle speed is outside the standard value, check
the MPI components by referring to GROUP 13A -
Troubleshooting.
8. Remove the timing light.
9. Turn the ignition switch to the "LOCK" (OFF) position
and then remove the MUT-II.

IDLE MIXTURE CHECK

MUT-II
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Turn the ignition switch to the "LOCK" (OFF) position,
and then connect the MUT-II to the diagnosis connector.
3. Set the timing light.
4. Check that the basic ignition timing is within the standard
value.
Standard value: 5_ BTDC ± 3_
5. Run the engine at 2,500 r/min for 2 minutes.
6. Set the CO, HC tester.
7. Check the CO contents and the HC contents at idle.
Standard value
CO contents: 0.1% or less
HC contents: 100 ppm or less
8. If there is a deviation from the standard value, check the
following items:
Diagnosis output
D
Closed-loop control (When the closed-loop control
D
is normal, the output signal of the oxygen sensor
changes between 0 - 400 mV and 600 - 1,000 mV
at idle.)
Fuel pressure
D
Injector
D
Ignition coil, spark plug cable, spark plug
D
Evaporative emission control system
D
Compression pressure
D
NOTE
Replace the three way catalyst when the CO and HC
contents are not within the standard value, even though
the result of the inspection is normal on all items.
9. Remove the timing light.