Smoking is caused by a few different things. First, you have to look at the color of the smoke to determine what's burning. If the smoke is blue(most common), then it's oil burning, if it's white, then it's antifreeze, and if it's black, it's unburned fuel. Blue smoke is oil escaping into the cylinder prior to ignition. On high mileage engines, the usual places are worn valve guides, where the oil runs down the valve stem and into the cylinder. On Occasion, a faulty PCV valve will cause this under certain moderate-high throttle conditions, but usually intermittently, with a sudden drop in performance. Worn Piston rings will also cause a constant blue smoke emission, another very common occurrence in high-mileage or worn engines. When you're burning oil, you will usually get excessive deposits on your spark plugs. Black smoke is a mismanagement of fuel by the car's computer and sensors. It means that it's running way too much fuel in the mixture of fuel to air, and not all of the fuel is burning. Black smoke isn't very prominent, and rarely lingers. The average person won't notice it as being out of the ordinary. Causes include faulty oxygen sensors, airflow sensor, map sensor, vacuum leak, and a myriad of other sensor issues. White smoke is caused from antifreeze leaking into the engine prior to ignition. It's usually caused from a blown head gasket or cracked head, and often is accompanied by a cylinder or two misfiring on startup. It's most prominent when you first start it up in the morning.
All of these require additional troubleshooting measures, and this is not an all-inclusive list of possible problems causing each smoke, however it should give you a good start on determining what's up with your car, as these are the most common causes. Hope this is what you were looking for.
Dec 30, 2009 |
1992 Pontiac Grand Prix