Note. Recommendation: If you have your Renault 19 regularly serviced in a workshop, the exhaust gas monitoring (exhaust gases) refers to the scope of service work.
In such a test, the machine is connected to a complex, expensive measuring device, the printer of which prints out the measurement results for their evaluation. If individual values do not meet the standard, then the test is not passed. However, if it is passed, it means that the exhaust system is working, air sucked through leaks does not enter the intake manifold, the air filter is not clogged and the gap of the spark plug electrodes is normal. Just in case, the ignition installation must also be checked.
If for Renault 19 need to pass «technical inspection of the vehicle», then first pass the control of the toxicity of exhaust gases.
If the Renault 19 has been operated only for short distances in winter for a long time, then you should change the oil. Condensation accumulated in the oil impairs the results of exhaust gas monitoring.
If you do not pass the exhaust gas toxicity control, do not immediately replace any expensive structural element, repeat the toxicity test in another car repair shop. Despite expensive measuring equipment, errors are still possible.