Emissions and Exhaust Systems

If the smoke is coming from the tail pipe then: Blue smoke is primarily from internal engine wear. If it's constant when the engine is on, then the rings etc are worn and need to be replaced. If it only is blue when the engine is cold or first started, the rings are worn but not gone completely. You get the oil seeping during the night and it burns off when the car is started in the morning. Black smoke is a fuel/air mixture suggestion problems with injection or carburation. Cause of black smoke is due to running rich in the fuel air mix. White smoke can and DOES come from coolant burn off in the oil due to a leaking or blown head gasket, cracked head etc. If you aren't sure or you don't know what you're talking about, don't advise. Wrong advice can be more damaging than the actual problem.

You need to rent / borrow / purchase an OBD II code reader to check the code.

On an overhead cam engine, the lobes on the cam push the rocker arms which push the valves open.

In a shop with a lift, correct tools, and replacement parts at hand, aprox one hour.

A conventional diesel engine will smoke excessively under load in situations whereby the engine rpm are too low for the throttle position ie, your throttle is opened too far and the revs are too low for the load the engine is expected to move- This is sometimes called "overfuelling". It basically means there is too much diesel being injected in relation to too little air being induced into the engine, in the same way that when you pour too much charcoal onto your barbeque fire it smokes because you are smothering it and there is not enough air. The amount of air that is induced into your engine is proportional to the engine rpm on most diesels like old landrovers, so don't change gear too early, or lug your engine. You will notice if you look in your side rearview mirror that when you go up a steep hill it may smoke excessively if you step on the gas pedal too much, but you will also notice that beyond a point you will get no corresponding increase in power, in other words you are just pouring fuel into the engine which is not even being burnt properly, and you are just wasting fuel and carboning up your engine. Some modern diesels overcome this problem by electronics. The gas pedal position is measured in conjunction with the air intake pressure and engine rpm and if you floor the pedal with the revs being too low, the computer will to some extent override your decision to prevent wasteful and incomplete burning of fuel.- This "drive by wire" system has its dissadvantages, imagine if a rat eats your wiring loom or there is a bad connection, you could have no throttle. the conventional system is better if you monitor the amount of overfuelling as you drive and tap off a bit when the smoke gets excessive.

On the old converters that have the plug in the bottom, when the plug comes out, the pellets of converter material fall out too. This "pelletized" converter is very heavy and is an archaic emissions device. You could put the plug back in and weld it so it doesn't leak, but this will fail an emissions inspection in most states, especially California. The better choice is to replace the entire converter and upgrade to a high flow "honeycomb" style. This is emissions legal and will actually increase fuel mileage by saving weight and lessening backpressure in the exhaust

The same as in any car.

If it's blue smoke it may be the piston rings or the valve guides are worn out.

If it's black smoke and you have a carburetor then it's using too much fuel, it's not getting enough air for as much gas that's being added. Could be the air cleaner is clogged real bad or the jetting is too rich.

If it's a diesel then the same thing, it may be running too rich or the injection timing is off a bit.

If its white smoke (steam), the engine is receiving unwanted coolant into the combustion area via a blown head gasket or cracked head.

If it hasn't been driven hard for a while and it clears up after some high speed d driving it is ok but if it smokes all of the time the rings or valve seals are bad.

It's probably burning coolant, which would indicate a blown head gasket or cracked or warped head. Anser one could be a cause. However, there could be other causes. The first thing that needs to be determined is if what you call "smoke" is actually smoke. IF it really is smoke, then it could be coolant OR some contaminant IN the fuel. Another possibility, if it is NOT smoke, is the condensation of water vapor which is a byproduct of the combustion process. For the condensation effect to occur however, requires cold ambient air temperature, and the effect would be enchanced IF the relative humidity were high, in addition to the cold air. j3h

It could be a few things. Its over heating and the fuel is burning up,you could be using the wrong fuel or if it has been doing it form the start(when you bout it) then it's fine or change the fuel your using.

A very small amount of white smoke at startup is normal and is nothing more than condensation in the winter. However combined with a loss of coolant with no apparent leak, overheating, white foamy substance on the underside of the oil fill cap, or overfull oil level, means you have a blown head gasket and or cracked head.

I have a 2003. A few months I was sitting in my car for a half hour idling and when I started driving again, white smoke, everywhere! I was going to have it towed to the dealership, but I decided to drive it instead. The smoke eventually went away, but I had them look at it anyway. They said there was oil in the intake and did a full fuel injection cleaning. I haven't had the problem again, though it went away before I got to the dealer, so maybe I wouldn't have seen it anyway.

Change your spark plugs!!

U have a blown head gasket,cracked cylinder head or cracked block.. The white smoke is from water getting into the Exhaust system.

Unfortuneately the most likely (only) problem is the ignition switch shorted internally If you look at the wires going into the switch you will most likely see that a black wire is melted This is a ground wire for the switch All the insulation may be bubbled or melted right off You need a switch and that wire replaced if you see this. Either way i think you need a switch

valve guides or valve guide seals or piston rings. in colder weather?

There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.

not the perfect air fuel mixture. normal under load and acceleration.

You cut it open hollow it out and weld it back together its easier to use a chunk of pipe to replace converter but if you need it emmisions tested either way your gonna fail miserably This answer is incorrect for the following reasons. This forum is NOT for illegal or immoral purposes and will not be tolerated. The correct answer is that it is against the Federal Law to tamper with or alter any automobile emission system. It can bring a Fine of $25,000 and or imprisionment. This is CLOSED to any further discussion. debrouxauto

== NO, defective exhaust manifold gasket will not cause this.
White exhaust smoke is a sign of coolant entering the combustion chamber. You more than likely as not, have a blown head gasket or cracked head. Stop driving this vehicle until you find out. Look for coolant in the oil, air bubbles escaping from the radiator, and a sweet smell at the exhaust. All indications of serious problems. A compression test will verify if you indeed have a blown head gasket. ==

Recently took my 2000 passat for emissions test. Afterwards I got emmisions workshop on the display and check engine light. I thought it might be a loose gas cap. Retightened no change!

You probably have an oil leak somewhere around the top of the engine. Valve cover gasket, leaking head gasket. When the engine warms up, it cooks it off and you smell it. http://www.autozone.com/servlet/UiBroker?UseCase=S001&UserAction=viewSimpleDiagInfo&Parameters=info

Yes, you can. But its pointless because a glssspack is a muffler. Just have a glasspack installed. Or a full catback glasspack exhaust system installed