4 Reasons Why Cars (Trucks & SUVs) Backfire, and What To Do About It!

We may get commissions for purchases made through links in this post. Thanks for the support! 👍

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.

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 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 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 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. 

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


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.

About The Author