1. Oil Burning: If the engine oil is leaking or burning, it can enter the exhaust system and create smoke. This can be caused by worn or damaged piston rings, valve stem seals, or cylinder head gaskets.
2. Coolant Leak: A leak in the engine's coolant system can allow coolant to enter the combustion chambers and produce white or gray smoke. This can be caused by a cracked cylinder head, a damaged head gasket, or a failing water pump.
3. Fuel Mixture Issues: An incorrect fuel mixture can also cause smoke to come out of the exhaust. This can be due to a faulty fuel injector, a clogged fuel filter, or a problem with the oxygen sensor.
4. Transmission Issues: If the transmission fluid is leaking or burning, it can also create smoke. This is most common in automatic transmission vehicles and can be caused by worn or damaged seals or gaskets.
5. Catalytic Converter Problems: A faulty or damaged catalytic converter can also cause smoke to come out of the exhaust. The catalytic converter is responsible for reducing harmful emissions, and if it is not functioning properly, it can cause the vehicle to produce excess smoke.
If you notice smoke coming out of the exhaust of your 91 Honda Prelude Si, it is important to have it inspected by a qualified mechanic to determine the cause and have it repaired.
