What Makes A Car Engine Backfire, Easy Fix Tips

Have you ever heard an engine backfire or currently have your engine backfiring and wonder what causes this to happen?  This article is designed to explain the most common engine backfire causes and what can be done to fix this issue. This is very common in Danfos and most public transport, but you might be wondering as the passenger the reason for this. 

Why Is My Engine Backfiring?

An engine backfire is when an internal combustion engine causes an explosion that occurs either in the air intake or the exhaust system instead of within the engine cylinder combustion chamber as designed.  This will usually be accompanied by a loud bang that will come from your engine and exit through your exhaust.

If an engine backfire does occur in the exhaust system this is called an afterlife because it is coming after the combustion process of the engine.  Most people will still call this type of issue an engine backfire.

What Are Some Common Engine BackFire Causes?

There are two ways that your engine can backfire either up back into the air intake of your engine or out in the exhaust system leading from your engine.  We have included the most common issues that can cause this to happen to your car’s engine.

• Your Engine Is Running Rich

If your engine is running rich this means that it is injecting more fuel into the cylinder of your engine than can be burned off during the combustion process.  When this happens the unburnt air and fuel mixture can be ignited in the exhaust chamber and shoot out of your car through your tailpipe. This will typically be accompanied by a loud bang from your exhaust and can also cause flames to shoot out of your exhaust tailpipe.

• Bad Ignition Timing

If your intake valve is still open when your spark plug ignites this will cause the spark plug to ignite the air and fuel mixture and shoot that out of the air intake port back towards the carburettor of your engine.  If you have a newer vehicle then you probably do not have a carburettor and will instead have an electronic throttle body. Backfiring your engine back through the air intake is going to be less likely to occur with an electronic fuel-injected system.

• Your Spark Plug Wires are Not Connected Properly

Your spark plugs are connected to your engine’s cylinders in a specific order as the engine is designed to fire the cylinders in a specific order that is determined by the engine manufacturer.  If you replace your spark plug wires and accidentally mix up how they are wired to the individual spark plugs this can cause your engine’s spark plugs to spark out of sequence which can lead to your car backfiring.  

If cylinder one is supposed to be sucking in the air into the cylinder but the cylinder’s spark plug ignites during that process this can cause your engine to backfire back through the carburettor.

This same issue can also occur on the exhaust side where if the cylinder is supposed to be pushing out the old air and fuel mixture but instead sparks while the exhaust valve is open it can cause your engine to backfire out of your exhaust pipe.

How Can I Stop My Engine From Backfiring?

• Check Your Spark Plugs

If your engine’s spark plugs are not able to fully burn the air and fuel mixture in the cylinder this can cause the air-fuel mixture to ignite in the exhaust manifold causing a backfire.  If you are unsure of when your spark plugs were last replaced it would be a good idea to inspect them for carbon buildup and corrosion.

If they do have a lot of carbon buildup on them it would be a good idea to go ahead and replace all of the spark plugs on your vehicle to eliminate this as a cause of your engine backfiring.

• Check Your Spark Plug Wires

If your vehicle’s spark plugs are worn out and are not sending enough charge to the spark plugs in your engine this can cause the air/fuel mixture in your cylinder to not burn off all the way.  

As you now know this can cause your engine to backfire out of the exhaust system if there is unburnt fuel in the cylinder. If you suspect your spark plug wires to be bad you can always replace them with new spark plug wires, new spark plug wires for your car should not be that expensive and it’s a relatively easy process.  

It is advised that if you plan on replacing your spark plug wires you do them one at a time to not get them mixed up in the process.

Check Your Carburetor

If your carburettor is sending too much fuel into the air intake of your engine this can cause your engine to backfire.  If you know how to adjust the carburettor on your car then you can adjust it to send less fuel into the air intake so that this no longer happens.  If you do not know how to do this yourself you may want to take your vehicle to a mechanic so that they could adjust it to correct this issue.

Sometimes stuff gets built up inside of engine carburettors which can also cause them to not operate as efficiently and they need to be cleaned.  If this is the case you can take some carb cleaner and an old rag to remove as much gunk and debris as you can to see if this helps out your situation.  Sometimes carburettors need to be eventually rebuilt or replaced altogether so also keep that in mind.

Conclusion

Hopefully, this article answered your question about why cars backfire and presented you with some solutions and things to check if your car is currently backfiring and you want to get it fixed.  

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If you are still having issues with your car backfiring after reading this article and checking out the solutions proposed here it may not be a bad idea to take your car to a mechanic so that they could look it over and determine the actual cause.