I would suspect it is burning oil. You may not see it but somebody behind you does.
That is called condensation. When you start the engine the exhaust system/pipes are cold. When the heat from the engine exhaust passes through the exhaust it makes it sweat. That is normal.
one of the causes is bad low quality fuel
No, not really. An engine will run without an exhaust (but you may get arrested). The exhaust simply directs waste gasses and quietens the noise. It plays no part in the running of the engine, but can reduce the performance if it causes on obstruction to the gasses.
The main reason for exhaust temprature is the problem with the injectors.the unburnt fuel from the combustion chamber flows to the exhaust manifold while engine works.This unburnt fuel burns in the exhaust manifold burns and causes high exhaust temprature.
The heat of the exhaust gasses will turn some polished exhaust pipes blue. This is very common with stainless steel exhausts.
we have a gas engine jenbacher 1006kw.we face a black shutdown due to exhaust back pressure high.
A restricted exhaust, possibly a plugged cataylitic converter.
grey exhaust smoke is caused by your engine burning oil during the combustion process. this could be caused by a piston ring that doesnt properly seal, or another leak in your engine.
Unburned fuel in the exhaust system causes the backfire from the exhaust pipe.
A vehicle that emits blue exhaust is experiencing an oil leak that has seeped past the engine seals and started to burn with the fuel. It indicates either a blown head gasket or an engine oil leak.
your oxygensensor is bad ,its screwed in to your exhaust manifold, about 30.00
if it is white smoke engine need to rebuilt.