Jeep Wrangler Sputtering And Backfiring

Backfiring is amongst the most disturbing Wrangler problems that you can encounter. It sounds essentially like a shotgun blast. A loud variation of this noise could be very frightening. There could be several reasons behind your Jeep Wrangler sputtering and backfiring. Some may include improper timing of your engine and poor quality spark plugs. It is also possible that your Wrangler engine may be running rich or there may be an issue with the plug wires.

Sputtering is a separate problem that usually signals deeper disturbances in your engine. It is typical for an engine to run out of gas to sputter. But if your gas gauge shows a full tank and you still experience sputtering, there could be a serious issue. The usual reasons for a sputtering engine lie in the fuel and the exhaust systems.

Understand the common reasons behind a backfiring engine

A Jeep Wrangler’s engine can backfire owing to many possible disturbances. There could be an issue with the vehicle’s ignition system or the variable valve timing. An excessively rich fuel mixture can also be the cause.

Backfiring usually arises in the vehicle’s ignition system

The ignition system of your Jeep Wrangler consists of spark plugs and ignition coil packs. It is also possible for the engine to use an ignition coil along with a distributor for each cylinder instead of a coil pack. Note that only the old Jeep Wrangler models are equipped with the distributors.

All these components of the ignition system are susceptible to getting damaged. This leads to the production of a relatively weak spark. Such that the ignition of the air mixture and the fuel inside the combustion chamber is inadequate. Much fuel is not utilized when this happens. This problematic mixture then burns at the exhaust stroke and creates a backfire.

Jeep Wrangler Sputtering And Backfiring

A rich fuel mixture could also cause backfiring

When the fuel mixture is excessively rich, there could be leftover fuel after the combustion. Backfiring is often the result of such an instance. Your Jeep Wrangler utilizes a number of sensors to adequately measure the amount of air and fuel that is led into the engine. The oxygen content of the exhaust is also analyzed well by these sensors. When some of these sensors fail to function properly, the fuel concentration is liable to become excessively rich.

There could be a problem with the ignition timing

Ignition timing is amongst the commonest reasons for backfiring. Most modern vehicles utilize variable valve timing for this purpose. When this VVT goes bad, your Wrangler can be left at the wrong timing and such a problem can arise. Jeep Wranglers utilize a timing chain belt to keep the camshaft and the crankshaft synchronized together. Any disturbance in this timing usually builds up the situation for a backfire.

Know how to diagnose your backfiring engine

The best way to assess this problem is by examining the engine check light. If this light is on, you can understand the source of the problem with the help of a code scanner. This technique will narrow down the list of possible causes and get you closer to the root cause. An understanding of the main cause is the closest you can get to finding a vital solution.

Check the spark plugs of your Wrangler

These are the easiest components to assess. Take a thorough look at the spark plugs and understand their health status. These spark plugs are amongst the common reasons behind backfiring engines. Bad spark plugs would require immediate replacement.

Check the other ignition components

After you have checked the spark plugs, assess the other important components of the ignition system. It is possible that sufficient spark isn’t being forwarded to the plug. So the fuel mixture won’t be fired completely and a loud backfiring sound would be created. It is common for spark plug wires to deteriorate. They should be adequately tested with the help of a voltmeter. Bad spark plugs will lead to spark leaking off the plugs. This will be actually visible during the night time.

Check the oxygen sensors

Deteriorated oxygen sensors can compromise the quality of your air-fuel mixture. This could create an excessively rich fuel that would cause backfiring. Such bad oxygen sensors can be duly replaced.

Check the timing chain and belt

If your timing chain has gone bad, your Wrangler could cause a delay in adequately firing the spark. If your Wrangler utilizes variable valve timing, even a problematic camshaft actuator can cause backfiring.

Understand the common reasons behind a Jeep Wrangler sputtering and backfiring.

The root causes of a sputtering engine are usually located in the exhaust and the fuel systems. There could be a leak in the exhaust manifold or the seals and gaskets of your engine could have failed. The problem could also lie in your catalytic converter, oxygen sensors, fuel injectors, mass airflow sensor, or spark plugs.

There could be a leak in your exhaust manifold

The exhaust manifold in your vehicle serves to collect exhaust gases. A leak in this area can lead to the sputtering of the engine. A problem in this region can also light up the check engine light and render incompetency to the engine performance. This problem could get very serious if the exhaust fumes interact with the plastic components or reach the car cabin. Escaping hot gases could have dangerous consequences for your car. It is best to get your sputtering engine checked by a mechanic as soon as possible.

Your Jeep’s catalytic converter could be inefficient

A rough and sputtering engine could also be the consequence of a failing catalytic converter. This problem will also trigger the check engine light. The failure of this component could also switch on your engine light. A failure of the catalytic converter system is usually accompanied by a rotten egg smell because of the burning sulfur components. This could also cause problems in starting your car.

There could be worn out gaskets and seals

There are numerous gaskets and seals in the exhaust system of your vehicle that could get worn out with time. Failing gaskets and seals also lead to sputtering engines. These parts are liable to get easily damaged and require replacement after some time. Any failure in their replacement would lead to further problems in your exhaust system that would deem more expensive repair.

Your oxygen sensors could have malfunctioned

Inefficient oxygen sensors cannot accurately measure how rich or scant the exhaust gases are. Your Jeep depends on this information to adjust the amount of fuel that will enter the engine. A failed sensor will supply less than normal or more than required fuel into the chamber and cause the engine to sputter. It is important that you replace your oxygen sensors on a timely basis.

Your spark plugs could be dirty

The spark plugs of your Jeep serve to ignite the fuel inside the combustion chamber. Improper spark plugs would lead to misfiring and sputtering. These plugs need to be replaced adequately.

Your fuel injectors could be dirty

The function of fuel injectors is to spray fuel into the cylinders. The fuel is then mixed with air and ignited. It is possible for the nozzle of your fuel injector to get clogged and result in a sputtering engine. This could also cause your Jeep to lose acceleration and power. It is possible to adequately clean the fuel injectors and prevent the problem early. Later on, they might need replacement.

Your mass airflow sensor could be dirty

The mass airflow sensor in your vehicle measures the amount of air that is entering the fuel injection system. This information is then sent to the vehicle’s computer so that the appropriate amount of fuel is supplied to the combustion chamber. A dirty mass airflow sensor would send the wrong information and result in sputtering.

There could be a vacuum leak

A leak in the vacuum system of your Jeep could also lead to sputtering. If this problem is left unchecked, your Jeep could begin stalling during acceleration.

Get your sputtering engine checked immediately

A sputtering engine is usually a symptom of a deeper underlying problem. Any delay in the correction of the underlying problem could have dire consequences for your Wrangler. Take your Jeep to the mechanic as soon as possible and find a viable solution to this problem.


You should never neglect any sputtering and backfiring in your Jeep Wrangler’s engine. While a backfiring engine usually signals a problem in the ignition system, a sputtering engine is a serious symptom that may extend deeper than you think. Both these problems require timely diagnosis and appropriate solutions at the right instance. It is recommended that you take your Jeep to the mechanic as soon as possible and get the issues repaired.

It is important that you adequately maintain your Jeep Wrangler so that such threatening problems do not arise. Keep your beast in the best of condition by timely replacement of the worn-out parts and quality service.

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