Note: Perform this check after checking the idle speed.
1. Before starting the inspection and adjustment procedures, prepare the vehicle (see section "Checking the idle speed").
2. Check that the basic ignition timing angle is within the nominal value (see section "Checking and adjusting the ignition timing angle").
3. If the tester was not connected during the check, turn off the ignition and then connect the tester to the diagnostic connector.
4. Start the engine and let it run at 2000-3000 rpm for 2 minutes.
5. Install the gas analyzer probe (CO and CH) into the exhaust pipe.
6. Measure the concentrations of CO and CH in idle mode, which should correspond to the nominal values.
Nominal values (not more than):
GDI engines:
- CO concentration - 0.1%
- CH concentration - 100 min⁻¹
Engine 4G15-MPI:
- CO concentration - 0.1%
- CH concentration - 100 min⁻¹
Engine 4G93-MPI:
- CO concentration - 0.5%
- CH concentration - 100 min⁻¹
Note: For GDI engine, measurements should be taken within 4 minutes of engine operation at idle speed.
7. If concentrations deviate from the nominal values, it is necessary to perform troubleshooting and check the fuel injection system. In most cases, it is sufficient to perform checks in accordance with the following points:
- a) Checking fault codes (output signal of the diagnostic system);
- b) (Except for 4G93-MPI engine) Checking the feedback control system:
Note: When the closed-loop control system is operating normally, the oxygen sensor output signal varies from 0 to 0.4 V and from 0.6 to 1.0 V at idle.
- c) Checking fuel pressure;
- d) Checking the injectors;
- d) Checking ignition coils;
- e) (MPI engines) Checking high-tension spark plug wires, g) Checking spark plugs;
- e) Checking the components of the exhaust gas recirculation system.
- g) Checking the fuel vapor recovery system;
- c) Compression check.
Note: The three-way catalytic converter must be replaced if the CO and HC concentrations exceed the nominal values with normal test results for all the above points.
(Original source of information: «MitsubishiMan.ru»)
8. Turn off the ignition and disconnect the tester.