Why is my car smoking from the exhaust
What Your Exhaust Smoke Is Trying To Tell You
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what your exhaust smoke is trying to
tell you we've all been there you catch
a glimpse of smoke circling in your
rear-view mirror and you instantly panic
but not all exhaust smoke is bad so
let's take a look at the combinations of
visible emissions from your exhaust and
what they mean black smoke the darker
smoke emitted from the exhaust is
generally nothing to worry about and is
linked with the balance of combustion
controlled by the ECU a darker visible
exhaust gas is due to an overly rich
fuel mixture created when the air fuel
ratio descends below the optimum ratio
the spark @ ignition can only combust a
certain amount of fuel in a cycle so
unburned fuel is pushed out into the
exhaust system and it's combusted
downstream of its intended combustion
chamber these conditions can be caused
by a leaking fuel injector a blocked
fuel return pipe a broken oxygen or air
flow sensor or a fuel pressure regulator
stuck closed a dirty air filter will
also prohibit clean air from making it
through to the combustion chamber not
only will this constrict the volume of
air entering the cylinders it will also
make for less efficient combustion blue
smoke blue looking smoke can be found in
cars that have unwanted oil mixing with
the air fuel mixture this means there's
a contaminant with the cylinders and
it's combusting along with the air and
fuel this cross-contamination is caused
by engine where to the cylinders Pistons
and valves along with failed seals a
damaged valve stem seal or guide will
also allow oil to make its way down from
the valve train above the cylinder head
while a damaged piston ring will allow
oil from the crankcase to squeeze its
way upwards and into the cylinders the
differing pressures within the
combustion chamber throughout the engine
cycle will lead to oil being sucked
through any leaks in the same way that
the air fuel mixture is sucked in via
the opening of the inlet valve this can
lead to lack of compression within the
cylinders and increased pressure within
the crankcase resulting in decreased
power blue smoke can be common in
modified and turbocharged cars by
turning up the power outputs in an
engine more stresses apply to each
component increasing where and the
possibility of oil leaks turbochargers
themselves can also fail allowing the
oil use to lubricate the turbine to
spill from bad seals into the cylinders
along with the compressed air adding to
the air fuel mixture contamination white
smoke white looking smoke probably isn't
smoke at all but steam and this can
potentially be nothing bad
or you could be a mile or two away from
an engine replacement you may notice
that from a cold start white smoke will
emanate from the exhaust tips this is
nothing to worry about and is created by
vapor from combustion if your car is
fully warmed up the ambient temperature
is reasonable and if your car is still
producing steam however you could be
looking at head gasket failure or even a
cracked cylinder head or block from
overheating the head gasket is designed
to keep the oil and coolant systems
apart along with cementing the cylinder
head and combustion chambers together a
split in the gasket will send liquids
into places they shouldn't be and if a
head gasket fails in a particular area
coolant will enter the cylinders the
engine will then try to compress and
combust water leading to potentially
catastrophic engine damage and also
steam pouring out of the exhaust the
size of the leak will dictate how much
steam is produced but often when a head
gasket fails you won't be able to see
out of the back window due to your car
suddenly morphing into an actual steam
engine if that's the case then pull over
as quickly as you can and pray to the
car gods so there you have it the
differences between engine smoke collars
and what they're trying to tell you
happy smoke diagnosing make sure you hit
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the BMW m2 and we're gonna teach you the
differences and how to initiate them
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