No visable fluid leaks but, lots of smoke coming from tailpipe on cold start. The smoke stops when the engine is warm. Car runs smooth and no problems at all other than the smoke coming out of the...
If this condition happens first thing when you start the car, especially in cold temperature(s) climate, you have nothing to worry about; this is normal. It is simply water vapor- a normal combustion byproduct.
Here's what happens: the exhaust manifold is attached to the engine.
The exhaust manifold takes the exhaust from each cylinder and combines it into the manifold.
The exhaust gases then pass through the exhaust pipes to the various components of the after-treatment system which include the exhaust gas recirculation (EGR) system, catalytic converter and the muffler.
Before the gasses reach the catalytic converter however, they pass the oxygen sensor. The oxygen sensor tells the on-board computer what the composition of the gas is, and diverts some of this gas back into the engine via the exhaust recirculation system.
The recirculated exhaust helps keep some of the toxic gasses from entering the rest of the exhaust system.
The recirculated exhaust gasses also cool the engine cylinders, which in turn, decreases fuel consumption.
Depending on the year, make and model of the vehicle, the exhaust gas recirculation system may have an electronic EGR valve or a vacuum-operated valve. The electronic EGR valve has additional parts, including an EGR solenoid.
If the EGR system does fail, you may hear a ping and the vehicle won't pass emissions. If the EGR valve fails in the open position, the vehicle will not idle properly.
When the exhaust gases reach the catalytic converter, it reignites the gases that are not burnt in the combustion chamber so that they are not emitted into the atmosphere.
The catalytic converter creates a chemical reaction, burning the excess gasses and toxic by-products from the engine combustion process.
And in so doing, the catalytic converter changes carbon monoxide and hydrocarbons into water vapor and carbon dioxide (which is its main function.) And that is what you are seeing coming out of your car's tail-pipe!
Mar 11, 2014 |
Mazda MX-5 Miata Cars & Trucks