The present study involves an empirical examination of a catalytic fuel reformer implemented in a diesel engine, utilising a zeolite catalysts. The attempt is made to study the recycle and reuse the Waste Cooking Oil (WCO) as an alternative fuel for diesel engine. For this purpose the WCO is cracked in the catalytic fuel reformer by using the catalyst zeolite. The output of the catalytic fuel reformer is in the gaseous form which is condensed using water cooled condenser. The oil obtained after condensing the reformulated gas is named as WCOZ. To know the suitability of using the WCOZ as alternate fuel for IC engines, the different properties of WCOZ are determined. Experimental results concluded that the performance and emission level are better than those of diesel fuel. This research presents the performance of catalytic converters manufactured from zeolite for the reduction of gas emissions of a CI engine. Hence an environmentally unfriendly WCO can be recycled into a useful resource and serves as an alternative source of fuel for diesel engine.