both technicians are correct
Step-by-step explanation:
exhaust gas recirculation sin bracket EGR contributes to limit the production of polluted gas mixture during internal engine combustion via an EGR valve with the help of exhaust gas recirculation nitrogen oxides production is reduced drastically especially when the engine runs on diesel black smoke exshaut making knocking sounds good be a clear indication of a bad EGR valve especially when the valve passage is blue musica Banda police blocking the valve opening variable decreases the power output or in this case of the knocks and the fear of ignited early when the machines operation at the given time is locked so the technicians are correct with the statements made. that is the explanation