1. Make sure that leaded petrol was not added to the tank when filling. RENAULT workshops can check the lambda probe using a diagnostic tool and determine what kind of fuel was added. If there is leaded fuel in the tank, at least two refills should be used up before replacing parts (two full tanks) unleaded petrol. This is necessary to "flush" the injection and exhaust systems.
2. Connect the gas analyzer and measure the CO content in the exhaust gases on a cold engine. Write down the obtained value. Since in this case the catalyst has not yet started working, the CO content will exceed 0.5%.
3. Warm up the engine to operating temperature until the radiator fan turns on and off twice.
4. Measure the CO content at 2500-3000 rpm. The maximum permissible value should be 0.3%. If the CO content is higher than 0.3%, disconnect the wire from the lambda probe. The lambda probe is located in the inlet pipe before the catalytic converter. If, after disconnecting the lambda probe, the CO content is the same as with the sensor connected, the lambda probe must be replaced.
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5. Install a new lambda probe and repeat the CO test. If it still exceeds the nominal value, the following systems or components should be checked:
- voltage (charge) of the battery;
- fuel supply;
- ignition system;
- engine operation at different speed modes (test drive);
- tightness of the exhaust system.
If no defects are found during this inspection, then remove the catalytic converter and inspect it for damage to the housing.
6. Turn the catalytic converter from side to side. If characteristic noises are heard inside the catalytic converter, this means that its internal filling is broken. In this case, the catalytic converter must be replaced.