Wastes are not useless, but they are used less. Wastes can be reduced by utilization not by destroying. The unobserved single-used low-density polyethylene (LDPE) plastic wastes are the sources that produce the fuel energy for the CI engines by pyrolysis. This downcycles the LDPE wastes. This neat LDPE plastic waste pyrolysis oil (LPWPO) has lower performance and slightly higher carbon emissions than diesel. To rectify this challenge, a premixed charge of air–acetylene is inducted into a 1500rpm 5.2kW CI engine at 1 to 4 lpm of flow rate. Acetylene is admitted into the inlet manifold to vary the mixture strength. Up to 26% of acetylene energy share is involved in the premixed combustion with LPWPO. At full load,4 lpm of acetylene induction with LPWPO oil produced 14.05%, and 22.96% increased BTE, and peak pressure than neat LPWPO respectively. At the same condition have 61.35%, 87.5%, 31.84%, 22.64% percentage reduction in soot (7.11g/kWh), CO (3.71g/kWh), UHC (0.18g/kWh), and CO2 (732.1g/kWh) emission than neat LPWPO respectively. However, the increased peak pressure increases the NOx emission. Therefore, Acetylene (4 lpm) induction with LPWPO is recommended for improved performance with reduced carbon and soot emissions. This method supports the LPWPO oil use in CI engines and indirectly supports the downcycling of single-use LDPE plastic waste in the environment.