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Bang, crackle, pop! These aren’t sounds you want to hear from your car’s exhaust. This is referred to as a backfire, which can result from quite a few different things that could be going wrong in your vehicle, and that is what we will be talking about today!
The primary reason that a car will backfire is that your engine is running too rich. This means there is too much fuel in the engine and insufficient air. This causes too much fuel, causing a small explosion and backfire or pop that you hear.
This, of course, is not the only reason for a vehicle to backfire, and a couple of other reasons could cause this.
Table of Contents
1. The fuel mixture is lean
As we discussed, if you have too little fuel in the cylinder when it ignites, it will only burn some of the fuel in the chamber. This leaves some fuel left over, and then that ignites off time and causes the backfire.
2. Engine timing is not on correct
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 timing, it can cause the backfire you hear.
This means that the cylinder explosions happen when the valve opens, not when it is entirely open. This causes the explosion to be late, causing the backfire.
To resolve this issue, I recommend going to a shop for this one; they will have the correct information to put your vehicle back in time and stop the backfire.
3. Your distributor cap is cracked
A distributor cap runs (Paid Link) all your spark plugs in older vehicles. This cap is what you see when you follow the line from your spark plugs to where they plug into the car. Once you find that cap, check for cracks.
If cracks are found, water may be getting in, causing the spark to transfer to a different spark plug than intended. This makes the explosions happen off time, causing the backfire.
Fixing your distributor cap is easy and relatively inexpensive. All you have to do is remove the spark plug wires from the lid and then remove the cap.
From there, compare the old and new caps and position them to be precisely the same. Then place the lid back the way the old one was, and make sure everything looks like it was, including spark plug wires. Bam (no pun intended), you are done.
4. 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 ignite correctly. This can again cause your vehicle to fire off time and cause a backfire.
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 turn off the distributor cap. Then replace them with a newly purchased set of cables (Paid Link).
This can quickly be done in around 5 minutes unless 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.
Frequently Asked Questions
Is a backfire terrible for your car?
From what I can find, it isn’t the end of the world if your car is backfiring. This is more because it means something else is wrong with your vehicle than the actual backfire causing issues.
Some people want their vehicles to “backfire”; however, this is more of an “afterfire,” meaning that leftover exhaust is caught on fire after it has left the engine. This is generally what you see in those modified cars, where it is obviously on purpose.
Can bad spark plugs cause backfire?
It is not your spark plug causing your vehicle to backfire. At the same time, 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. Good spark plugs give 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 entirely on purpose. People like this because it draws attention and can sound cool.
However, these are done on purpose and are typically done (on modern vehicles) by modifying the ECU to cause the car to run rich (similar to how diesel trucks can “roll coal”). 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 or modifying the ECU, or there are plenty of DIY ways. I want to do it right and replace the exhaust system to give you the right sound without breaking anything.
What should I do if I don’t know why my car is backfiring?
If you are unfamiliar with vehicles and cannot diagnose your car, contact and schedule an appointment with a trusted shop.
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 most significant investments, and you should take care of it.
So there you have it; the main reason for a vehicle to backfire is that 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 make sure you know what you are doing or have a professional make that happens.