What is backfire in engine. It's reason and precautions.

What is a backfire,

 

Backfire is a part of combustion phenomenon.
It produce during the power stroke when air fuel mixture comes into the cylinder for burning then some unburnt fuel remain and during exhaust it goes out into the exhaust system and there it ignite and produce a loud sound this unlike sound is called as backfire.

A backfire occurs inside the exhaust system.

Due to this backfire a flame may visible in some conditions. This noice is comes due to improper tunning of engine.

Causes
Backfire occurs in the engine have some issues of it's emission system
Like problem in intake valve, problem in exhaust valve, or problems in catalytic converter.

Or

When a drive shift his car sudden in high speed then engine cylinder got richer air fuel mixture and this results in more unburnt fuel goes into exhaust system that also lead to backfire with a boom sound.

And this boom like sound damege various parts of engine like it damage engine's both valves and it damage exhaust systems catalytic converter and harms tailpipe system.

Now we know the reason behind the car engine backfire.

There are 4 major reason that leads to backfire

Sign. Of backfire is a loud sound and a flame comes out through the exhaust pipe.

If this type of sign seen then there is a significant problem with the internal combustion engine.

This problem damage the engine and waste more fuel.

but now a days most modern cars have computer controlled fuelling system that prevents backfire from the trail pipe.
Even there is backfire done by engine then most of all technician improve this and control backfire.

In this article we kome some reason behind the backfire.
There are 4 common reason for backfire that are discussed below in a engine.

Why do Engines Backfire? Reason #3: Bad Engine Timing

An engine backfire take place when fuel blast outside of the combination cylinder
In normal engine when correct precisely air fuel mixture at exact ratio goes into the cylinder then at right time spark plug provide a spark and moment of piston goes into motion, and we get power stroke.

If this is timing of spark plug be a little bit late then all air fuel mixture doesn't burn and some remaining part goes into the exhaust pipe by engine cylinder, when this unburnt fuel reaches into the tailpipe because of it's hotness it generates a flame in presence of atmospheric oxygen resulting a loud noice is comes out from the tailpipe
Some time this flame is visible from outside of the tailpipe.

Solution

Some Modern engine timings are now controlled by ECU , and this work very precisely. Due to this most engines  burn upto 100% of the fuel in each combustion chamber each and every time.
And reduce backfire in the engine.

Why do Engines Backfire? Reason #1: Rich Fuel Mixture

Modern engines can still backfire, and a poor fuel ratio is one common cause of this. For starters, let's imagine there is too much fuel in the engine and not enough air. The spark inside the chamber may not burn up all the fuel, allowing a little extra gasoline vapor to enter the exhaust, and lead to a backfire.

This can be caused by a faulty mass airflow sensor or a clogged engine air filter "choking" the engine and not allowing enough oxygen to flow into it. Or, it could be caused by leaking fuel injectors forcing too much fuel into the engine. You'll want to have these issues looked at by the professionals, otherwise you'll be wasting a significant amount of fuel.

Why do Engines Backfire? Reason #4: Lean Fuel Mixture

The opposite problem can lead to the same result. If there's too much air in the cylinders at the time of the spark, and not enough fuel, the spark won't be able to ignite all the fuel at once. Yet again, leftover fuel vapor will flow into the exhaust and could combust there in a backfire.

Common causes of a lean fuel mixture include a vacuum leak allowing the engine to suck too much air; clogged fuel injectors not adding the correct amount of gasoline to the cylinders; or a bad fuel pump that's no longer pumping enough fuel from the tank to the engine.

Why do Engines Backfire? Reason #2: Older Engine Problems

If you've got a classic ride, that older engine technology under the hood is more prone to backfiring. That's because the systems on older engines aren't computer controlled, and thus will need constant adjustments often called a tune-up.

For example, modern cars no longer have spark plug wires. They're equipped instead witn coil-on-plug designs that increase the consistency and control with which the engine fires its sparks. On an older car with spark plug wires, wires that get crossed or installed in the wrong order can inadvertently cause a spark to fire in a cylinder when it's not supposed to. This could cause a significant backfire.