This Is Why Cars Backfire [And how to fix it]

I have been spending a lot of time thinking about cars lately, and was thinking “Why do cars backfire?”, so I have done some research, and have come up with some great answers to that question.

The primary reason that a car will backfire, is because your engine is running too rich. Basically this means that there is too much fuel in the engine, and not enough air. This causes there to be too much fuel, causing a small explosion, and backfire, or pop that you hear.

What other reasons are there for a vehicle to backfire?

This of course is not the only reason for a vehicle to backfire, and there are a couple other reasons that could cause this.

Fuel mixture is lean

Much like we talked about before, if you have too little fuel in the cylinder when it ignites it won’t burn all of the fuel in the chamber. This leaves some fuel left over, and then that ignites off time, and causes the backfire.

Engine timing is not in time

Did you know that there is a specific timing that an engine should be running at to make it run correctly? If your engine is delayed in its timing it can cause the backfire that you are hearing. 

Basically this means that the explosions that happen in the cylinder are happening as the valve is opening, and not when they are completely open. This causes the explosion to be late, causing the backfire.

How to get your engine back in time?

I would recommend going to a shop for this one, they will have the correct information needed to put your vehicle back into time, and to stop the backfire. 

Your distributor cap is cracked

All of your spark plugs in newer vehicles are run by something called a distributor cap. This cap is what you see when you follow the line from your spark plugs, to where they plug in. Once you find that cap, check for cracks.

If cracks are found, it is possible that water is getting in, causing the spark to transfer to a different to a different spark plug than intended. This makes the explosions happen off time, causing the backfire.

How to fix your distributor cap?

This is actually a simple job, and relatively inexpensive. All you have to do is remove the spark plug wires from the cap, and then remove the cap itself.

From there, compare the old and new cap and position them to be exactly the same. Then place the cap back the way the old one was, and make sure everything looks like it was including spark plug wires. Bam, you are done.

Spark plug wires have carbon tracking

Over time, carbon buildup can cause your spark plug wires to not transfer the right amount of electricity to make the fuel in the cylinder to ignite correctly. This can again cause your vehicle to fire off time, and cause the backfire.

Replacing your spark plug wires

This is probably the easiest fix of anything on this list. All you have to do is remove the wires from the top of the spark plugs, and off of the distributor cap. Then replace them with a newly purchased set of wires. This can easily be done in around 5 minutes or so. 

Unless of course the spark plugs are on the back side of an engine, where they aren’t easily accessible. This is common in front wheel drive V6 engines.

Is a backfire bad for your car?

From what I can find, it appears that it just isn’t great if your car is backfiring. I believe this is more because it means that something else is wrong with your vehicle, than the actual backfire causing issues.

Now some people actually want their vehicles to “backfire” however this is actually more of an “afterfire” which means that leftover exhaust is caught on fire after it has left the engine. This is generally what you see in those cool cars, where it is obviously on purpose.

Can bad spark plugs cause backfire?

It probably is not your spark plug causing your vehicle to backfire. While it is more likely to be something else causing the backfire, like the distributor cap. 

It is best after resolving this to replace your spark plugs, due to any buildup that has happened. Having good spark plugs gives you the best ignition, making your vehicle run much better.

How do I make my engine backfire?

Now some cars out there will crackle, or have an afterfire. This isn’t a backfire, and is actually completely on purpose. People like this, because it draws attention, and can sound cool.

However these are done on purpose, and are normally done (on modern vehicles) by modifying the ECU to cause the vehicle to run rich.

You will find this stock on quite a few sports cars nowadays.

If you want to make your car do this, you can do it by replacing the exhaust system, modifying the ECU, or there are plenty of DIY ways of doing this as well. I personally would want to do it right, and replace the exhaust system to give you exactly the right sound, without breaking anything.

What should I do if I don’t know why my car is backfiring?

If you aren’t familiar with vehicles, and aren’t able to diagnose your car yourself, make sure to contact and set up an appointment with a trusted shop of your choice.

Not having your vehicle looked at when it is backfiring can cause damage to your car, and no one wants that.

Remember, your car is one of your biggest investments, and you should take care of it.

Conclusion

So there you have it, the main reason for a vehicle to backfire is because it is running too fuel rich, making the explosion happen off time. There are of course many other reasons for this, but this is the most common.

You may also want your vehicle to backfire (afterfire), but just make sure you know what you are doing, or having a professional make that happen.

If you are having this issue with your truck, once it is fixed, you may want to read through this article I wrote about how to make money with your truck.