ACADEMICS will today back taxi and minibus operators urging the Government to rethink its controversial plan to convert diesel vehicles to petrol. Four Hong Kong Polytechnic University lecturers will call on the Government to get tough on car maintenance and control rather than eliminate diesel vehicles. They say more public funds should be allocated to train mechanics, newly imported diesel cars should be upgraded and the law should demand more frequent check-ups on cars. The Government recently announced a five-year plan to convert diesel-run taxis, minibuses and school buses. A package of financial incentives will help meet increased costs. But operators objected and sponsored a study by the academics on the two fuels, to be presented to the Government today. The experts concluded it is possible to keep diesel vehicles if maintenance is improved. One of the academics, Lo Kok-keung, associate lecturer in mechanical engineering, said diesel fume problems were caused by poor maintenance. 'The mechanics don't need to be qualified at the moment, and there isn't a set of standards for them to carry out maintenance,' said Mr Lo. He said the Government should legislate to restrict the sulphur content of newly imported diesel vehicles, which should be fitted with a soot burn-off filter to help reduce fume particles by 70 per cent. Mr Lo said the study showed operators' costs under the planned conversion scheme would increase after three years, despite financial incentives. 'It's more economical to use diesel in the long run,' he said. 'Diesel vehicles are being used in other countries, why can't Hong Kong do the same?' Other academics involved include Hung Wing-tat, assistant professor of civil and structural engineering; Dr Stanley Yuen, head of the Office of Industrial Development and Dr Cheung Chun-shun, assistant professor of mechanical engineering.