Why is My Exhaust Popping?

You’ve probably heard it before; a loud popping or banging sound comes from a vehicle passing by, ranging from a light pop to what could be mistaken for a gunshot depending on the severity of the issue or type of exhaust setup.

One of the main responsibilities of your exhaust is to help make your vehicle as quiet as possible. If you hear loud backfire and popping from your tailpipe and don’t have it set up to do that intentionally, it can be concerning.

While some automotive enthusiasts will tune their vehicles to produce this popping sound in a (more) healthy and sustainable way for the motor and emissions equipment, the vast majority of the time it’s something that should be avoided and addressed promptly when it happens. 

So what’s making this noise occur, and will it cause any damage to your vehicle? In this article, we’ll go over these questions and what to do if you’re experiencing a similar issue!

What Makes Exhausts Pop?

Internal combustions rely on, well… internal combustion within the cylinder. When something goes wrong and one of these explosions happens externally instead, you get the loud banging sound we’re discussing.

This often happens when unburned fuel is able to escape through the exhaust valve. The fuel will make contact with the hot exhaust pipes, and eventually combust, creating a mini explosion within your exhaust. 

A similar issue occurs when combustion happens during the exhaust stroke as the exhaust valve is open. With the valve to the exhaust system being open, the combustion will be heard as a loud pop from the tailpipe. 

So, how does this happen in the first place? 

Causes of Exhaust Backfire

Rich Condition

When a vehicle is running “rich”, it means there is a surplus of fuel being added to the cylinders for combustion compared to the ratio of air. If running with an improper ratio, combustion will be slowed and there will be unburned fuel left in the cylinder.

This extra gasoline can combust either during the exhaust stroke or after the excess fuel has escaped into the exhaust system, causing the startling bang sound. 

Rich conditions are caused by various mechanical issues, including a failed mass airflow sensor, faulty O2 sensor, leaking injectors, and many more. If you’re experiencing a rich fuel mixture, avoid driving your vehicle and have it inspected by a trusted automotive professional.

Bad Timing

The timing system in an engine is responsible for keeping the four processes that need to occur for proper combustion in perfect synchronization. This is most often accomplished through the use of a belt or chain, but these can be knocked out of proper timing due to problems with the chain/belt itself or the tensioner. 

When any of these four strokes happen a tick early or late, it can cause problems with combustion. When full combustion has not occurred, there may be leftover fuel pushed into the exhaust system leading to backfire. 

Timing issues need to be taken very seriously, as they have the potential to cause catastrophic engine failure. 

Faulty Spark Plug(s)

Spark plugs play one of the most crucial roles in the combustion within an engine, creating ignition. These plugs rely on short electrical pulses to ignite the air/fuel mixture and push the piston. 

Spark plugs on orange towel
Myke2020, Public domain, via Wikimedia Commons


If the spark plugs or any accompanying electrical components such as fuses and wires encounter an issue it may leave unburned fuel within the combustion chamber. This fuel will either combust at the improper engine stroke or be pushed into the exhaust system and combust there. This issue may be accompanied by a misfire code from your check engine light. 

Exhaust Service & Repair at Matson Point S

If you’re looking for high-quality exhaust diagnostics, maintenance, and repair, the ASE Certified technicians at Matson Point S in Riverton, Utah have the expertise and equipment to properly take care of your vehicle! Give us a call or schedule online with us today.


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