The core objective of this study is to pull back the worsened combustion, emission, and performance characteristics of a CI engine fuelled with waste tire pyrolysis oil diesel fuel blends. Four fuels are tested in the experiments. These are (1) 100% diesel fuel, (2) 20% waste tire pyrolysis oil ? 80% diesel fuel, (3) 10% pyrolysis oil and 80% diesel fuel containing 10% waste biodiesel, and finally, (4) 10% waste tire pyrolysis oil and 80% diesel fuel containing 10% waste fusel oil. The tests are performed at a constant engine speed of 2400 rpm, and varying engine loads from 3 to 12 Nm with intervals of 3 Nm. In the results, it is noticed that using of waste tire pyrolysis oil diesel fuel blend is reducing the brake thermal efficiency down to 9.13% for waste tire pyrolysis oil diesel fuel blends, however, this reduction is being pulled back by 7.51%, and 3.82% with the addition of waste biodiesel, and fusel oil, respectively as compared to that of diesel fuel. On the other hand, waste tire pyrolysis oil diesel fuel blend increased the brake specific fuel consumption by 21.78%, however, this increase is being pulled back by 8.89%, and 12.57% for waste biodiesel, and fusel oil, respectively. The increase in carbon monoxide for waste tire pyrolysis oil-diesel fuel is 7.09% in comparison with that of diesel fuel. However, with the addition of biofuels, carbon monoxide is being dropped by 7.69% for waste biodiesel, and 19.23% for fusel oil due to the high oxygen contents of waste biofuels. Moreover, waste tire pyrolysis oil-diesel fuel blend is increasing nitrogen oxide by 7.09%, but this increase by 4.64% with the addition of waste biodiesel. On the other hand, the addition of fusel oil is converting the increasing trend of nitrogen oxide into a reduction of 3.09% owing to fusel oil?s water content. As a consequence, this research is proving that the waste biofuels are able to improve poor combustion, emission, and performance characteristics of binary waste tire pyrolysis oil diesel blend with the doping of waste biofuels, and suggesting ternary blends rather than waste tire pyrolysis oil alone for diesel engines. Moreover, it is noticed that burning waste products is a very effective tool for both waste management and alternate to fossil fuels. ? 2021 Elsevier Ltd. All rights reserved.