[DownloadMan]

About the black smoke being unburned fuel is incorrect. Diesel fuel is in fact almost clear, but they put a die in the fuel to give it a colour, so you can differentiate from other fuel's. Unburned fuel is in fact almost invisible, it is the burnt carbon particles mixed into the unburned fuel, that you actually see during Acceleration, created because there is not enough air mixed into the combustion process to fully burn the fuel into carbon dioxide gas, so a carbon solid is produced instead. In Fact unburned fuel is always emitted in all internal combustion engines, at all speeds, but more so during heavy Acceleration and this part of the fuel is dangerous""""""

Exactly what I said, but changed into double talk,,




Direct injection is better for even fueling and atomization on newer direct injection gas engines but still they can't attain high enough pressures on gasoline to inject at the pressure of compression or at the time of firing so it in injected and compressed then fired with a spark,Just the same as carburated engines, but a more even distribution of fuel, be nice if they could do it at or before top dead center, but they can't as they do and have always done with diesel. Diesel engines have enough heat of compression to ignite diesel, cars don't have that kind of heat so is always done with spark. Diesel engines usually run at 16 to 1 compression ratios or more and the heat of compression is more than hot enough to melt tin, therefore the extra heavy construction. gasoline would go off in them but all you have is an explosion and thats it, No power,,Pump gas is no good at high compression pressures. so auto engines are average 8-1 or at most 10-1 unless specialty engines running on special high octane fuels and then you can go higher.just like running low octane[reg gas] in high performance engines,They PING because of explosion in the cyl. they are higher comp. so need premium grade gas as the more octane the slower the fuel burns, reg. in the cyl. explodes,,Hitest starts and increases in burn for the duration of the power stroke. thats why you see flames coming out of the stacks on NASCAR and other racing engines,,special octane fuels=longer burn.

Black smoke from gas engines as well as diesel is still unburned fuel, more is going in than will burn and is dropped out the exhaust, more fuel than can be burned for reasons of to much fuel for the volume of ox in the air, or of just air because of plugged air filters,, to rich gas mixtures and low compression, to low heat of combustion,bad injection timing, plugged or damaged injector nozzles, low turbo boost pressures allowing to much fuel volume,Both gas and diesel, even the newer diesels will smoke when stepped on and fuel flow is increased before turbo boost levels come up to required pressures, and they have a regulator on them that does not let to much fuel in until turbo pres. is up.
gas engines also smoke black it by chance the choke is stuck or the cold starting device on the injection system is not working correctly,, any number of reasons can cause it,,but black smoke is always unburned fuel, gas or diesel and there is not anything else in this world that will cause it,And the dye, red yellow, brown or green is of no consequence, Grey or white smoke is oil smoke.