2. Check the main ignition timing, which must correspond to the nominal value.
Main ignition timing: 5°±2°to TDC
3. Turn off the ignition and connect the MUT-II device to the diagnostic socket.
4. Start the engine and for 2 minutes, increase the engine speed to 2500 min1.
5. Install the gas analyzer probe (CO and CH) into the exhaust pipe.
6. When the engine is idling, measure the concentrations of CO and OH, which must correspond to the nominal values:
- CO concentration - no more than 0.5%;
- CH concentration - no more than 100 ppm.
7. If CO and CH concentrations are not within acceptable limits, check the following:
- diagnostic codes;
- closed-loop control (in the case of normal operation of the control system in closed loop mode, the output signal of the oxygen concentration sensor changes from 0 to 400 mV and from 600 to 1000 mV at idle);
- fuel pressure;
- fuel injectors;
- ignition coil, high-voltage wires and spark plugs;
- EGR system and valve;
- no leakage in the exhaust gas recirculation system (EGR) and EGR valve;
- compression in the engine cylinders.
Note. If the CO and CH concentrations exceed the nominal values, even with all positive checks, replace the three-way catalytic converter.