Black Smoke From Exhaust: Top 4 Causes

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Emitting black smoke from the exhaust during start-up is usual in some cars but it fades after the engine warms up. However, if this continues, then there is something wrong with the engine. Depending on the root cause, you may need a professional mechanic or you make fix yourself.

Ideally, your car should not release a lot of black smoke, especially in newer cars. They still have filters in the engine to prevent this. Older cars on the other hand may blow a little more smoke than usual. This can be remedied by proper maintenance. In this article let us explore the top four causes of black smoke from the exhaust.

Clogged Air Filter

Causes of Black Smoke From Exhaust

A clogged air filter is the most common culprit of black smoke. Air is a vital component of the combustion process – Your engine cannot burn fuel efficiently without sufficient air. This partially burned fuel turns into black smoke. Moreover, if there are carbon chucks in the filter, it could clog your EGR valve. The symptoms include loss of power, fuel inefficiency, and emission of black smoke from the exhaust. If this is the case, you may need to replace your air filter.

Leaking fuel injectors

Fuel injector rhythms accurate volume of fuel to the vehicle’s intake manifold. It will go through the combustion chamber and be mixed with oxygen to improve burning efficiency. Furthermore, fuel injectors make sure that the fuel is sprayed towards the engine inlet valve. In case the fuel injector becomes clogged with debris, it cannot perform its job properly. As a result, the extra fuel forms a solid carbon residue that is emitted as black smoke every time you accelerate.

High pressure on fuel regulator

The fuel pressure regulator works on a precise pressure range. A vehicle may not run or will run inefficiently with the faulty regulator. Over fueled engine caused by high pressured fuel regulator or bad coolant temperature sensor can lead to poor fuel mileage, black smoke from the exhaust, and engine running rough.

A defective O2 sensor can also cause a vehicle to run either rich or lean. If your car is running excessively rich, it can cause black smoke coming from the exhaust pipe.

Black smoke from the exhaust of a diesel engine

Known to many as highway smoking machines, diesel engines producing black from the exhaust is considered normal during the 60’s up to the ’80s. But it is not normal if the vehicle is a late model car or truck with a “clean diesel” engine If your car or truck is older it must have accumulated a lot of combustion products. Since diesel is crude fuel without any detergents, vehicles with diesel engines are susceptible to carbon buildup.

In most cases, adding a detergent additive to your diesel fuel would resolve the issue. This should be done regularly. But if it still produces black smoke, it’s possible that the engine is getting too much fuel. If this is the case then incorrect injector timing or an injection control problem could be the culprit.

Cleaning agents are popular for removing the grime from your car’s engine, but what about Sea Foam? The detergent product is supposed to be good for breaking down gunk in engines, but can Sea Foam hurt your engine?

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