Why Does My Dual Exhaust Only Smoke on One Side?

Many dual-exhaust vehicle owners have experienced a common issue with their exhausts. They keep searching for an answer to “why does my dual exhaust only smoke on one side?” In this discussion, I am here to help you with its answer. You will learn about the reasons and possible solutions to the one-side smoke problem.

Precisely, the smoke only comes out of one side, either the driver’s side or the passenger’s side. The consequences could range from reduced performance to a higher risk of fire hazards.In short, there are multiple reasons for smoke coming out of one side of the dual exhaust, including a clogged catalytic converter and a damaged filter.

Let me dive deeper into the problem and find its solution. I expect you will read the whole post to solve your dual exhaust smoke problem. Possibly, you won’t need to call a mechanic after reading it.

Functions of a Healthy Dual Exhaust in a Vehicle:

Primarily, a dual exhaust system is an aftermarket or factory-built system designed to improve the engine’s performance.It works just like a single exhaust with a few more facilities. Also, it can increase engine efficiency.

It consists of two exhaust pipes that run from the engine to the rear of the vehicle. In the end, there are two separate mufflers and tailpipes.

As I said, it functions to increase the flow of exhaust gases out of the engine. The engine can expel exhaust gases more quickly and efficientlyby having two exhaust pipes. Thus, your vehicle gets better horsepower and torque, and reduced backpressure on the engine. As a result, you can save fuel and reduce emissions.

Dual exhaust can produce a more aggressive sound than a single exhaust system. Even, the separate pipes and mufflers allow for more control over the sound. It gives the owner a more sporty or aggressive tone.

Why Does My Dual Exhaust Only Smoke on One Side?

The purpose of a dual exhaust system is to improve the performance of the vehicle.It can also enhance the appearance of your vehicle.So, having a functional dual exhaust is an essential matter.

Reasons for Smoke Coming Only One Side

Every vehicle performs 4 actions:

  • Air and fuel intake
  • Compression of air and fuel in the piston
  • Combustion in the combustion chamber by spark plugs
  • The flow of power and release of smoke through exhaust simultaneously

While combusting the air-fuel mixture, some leftover comes out as gas through the exhaust. Sometimes it comes out only one side of the dual exhaust. Thus, a single exhaust system may have multiple exhaust systems.

A 4-cylinder vehicle has one exhaust manifold while larger engines have two. Vehicles with two manifolds have single exhausts with dual exhaust tips. Besides, you will find an H pipe placed just before the converters with the dual exhaust. It controls back pressure when your vehicle gets boosted HP.

Therefore, dual exhaust smokes only one side. It might allow more effective ways to provide air-fuel mixture exchange. In general, the exchange of exhaust and intake hasan impact on horsepower.

Here are some possible reasons to get this problem:

Damaged or Clogged Muffler

A damaged or clogged muffler on one side of the dual exhaust can restrict the flow of exhaust gases. Eventually, it can cause smoke to come out only on that side.

Blocked Exhaust Pipe

An obstruction in the exhaust pipe, such as a buildup of debris or a damaged section, can cause the issue.

Faulty Oxygen Sensor

A malfunctioning oxygen sensor can cause the engine to run too rich or too leanwhich can be another reason.

Damaged Catalytic Converter

A damaged catalytic converter can cause the exhaust gases to back up. As a result, it leads to smoke coming out of only one side of the dual exhaust.

Unequal Engine Compression

Unequal engine compression between cylinders can cause one side of the engine to run hotter than the other. Therefore, the problem may appear.

Fuel System Problems

Fuel system issues such as a clogged fuel injector or a faulty fuel pressure regulator can cause one side of the engine to run inefficiently. Then, you may see smoke coming from one side of the exhaust.

Discussions for Further Understanding (Reasons & Solutions)

Let’s check out some conversations related to this issue:

Someone asked, “How do you fix a dual exhaust that only smokes on one side?” on Quora, and he got these replies:

If the car is smoking only on the one side of a split system, you likely need rings or head work on that side of the engine I would think.” (Source)

On Bimmerpost, I found a similar conversation:

I’ve noticed that when I first start up the car only the passenger side exhaust has the smoke coming out of it…”

He got several replies:

Normal – there’s a valve that opens/closes the driver side.”

Normal. If you look at older stock e90/92 335i cars you will notice one exhaust tip is much cleaner than the other.”

Normal… second one opens up when full throttle.”

These replies point out that one side of the smoke is not a big deal. And the last comment assures that smoke will come out on both sides when you drive the vehicle at full throttle.

In another forum named Pelican Parts, I have found a thread:

I’m trying to find out why I get smoke coming mainly out of the left side exhaust outlet and not the right on my 81 930.”

There, the author of this post got these replies:

Maybe the oil that had leaked into the muffler is still burning off and the baffles limit it to one area and that manifests itself only on one side?”

I’d remove spark plugs and see if there’s wet oil or burnt oil carbon buildup on any of them.”

These replies accuse the oil leakage into the muffler and wet or burnt oil-carbon build-up to cause exhaust smoking only on one side.

Someone asked about this problem on FT86Club. He got a reply: “I would guess a poor pipe layout…”Other replies were just like the Bimmerpost above. Hence, they mostly refer to the issue as very normal.

Like all these discussions, you can find many people report about this problem. You can check these threads by clicking on them: Stovebolt, Hyundai-Forums, Nasioc Forums, etc.

How to Solve Dual Exhaust SmokesOnlyon One Side Problem?

When your vehicle is releasing leftover gas through one side only, there must a possibility of deterioration. Maybe there is internal corrosion happening for the acidic moisture. Unfortunately, moisture can damage both the engine and exhaust system. So, you should treat the issue as soon as you can.

Some other issues of the problem can be road and weather. If there are salt or chemicals on the road, they may impact the dual exhaust system. As a result, external corrosion will take place and the system will fail accidentally.

So, you should take your vehicle to the mechanic or check yourself if the smoke is coming out only on one side or not. Then, you can save your fuel and get sufficient torque and overall performance.

You may also follow these instructions:

Check for Obstructions

Check the exhaust pipe for any blockages, such as debris or a damaged muffler.

Inspect for Leaks

Another potential cause of the problem is a leak in the exhaust system. Inspect the system for any visible leaks and listen for any unusual noises coming from the system.

Check the Catalytic Converter

Have your mechanic check the catalytic converter and replace it if necessary.

Check the Oxygen Sensor

Check if the oxygen sensor is functional. If not, call the mechanic and replace it if necessary.

Consider Upgrading the Exhaust System

A high-performance dual exhaust system can improve engine efficiency. It can reduce the risk of future problems. So, upgrade the current dual exhaust system for better results.

Final Words

So, I guess you have found the answer to “why does my dual exhaust only smoke on one side?” I hope you have read the whole post. Try to follow the reasons and solutions to quickly identify any cause and treat accordingly.

Thanks for your time. Happy Driving