Emission norms are introduced to limit exhaust pollutants from vehicular engines to improve and control ambient air quality. Thermodynamic simulation results showed the possibility of upgradation from Euro-2 to Euro-3 emission norms using a low pressure inline fuel injection pump. Geometric parameters of piston bowl, injection nozzle were adjusted and the combustion parameters like swirl start of injection, controlled injection and jet penetration were fine tuned to achieve the emission norms using the cost effective inline fuel injection pump. This fuel injection system is tolerant to indifferent fuel quality as it is lubricated by engine oil and the clearances within the pump do not demand exceptional lubricity or cleanliness of the fuel. The exhaust is polished off soluble organic fractions, carbon monoxide and hydrocarbons using a lightly loaded diesel oxidation catalyst that is tolerant to 500 ppm sulphur in fuel. Data from 20 engines showed emission is consistent. Experiments in the field showed the new Euro-3 engines are equal in fuel economy to the Euro-2 engines.