Why does my exhaust pop when I let off the gas?

An afterburn or backfire from a vehicle's engine on deceleration happens when unburnt fuel combusts or ignites in the exhaust pipe. The result is a loud bang or pop when you move your foot off of the gas pedal. Take note that this instance can occur in many vehicles, including trucks and motorcycles.
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What causes exhaust popping on deceleration?

Decel popping is caused by the detonation of unburned fuel in the exhaust pipe. This happens with high flow exhausts that allow more fresh air to be pulled into the pipe, causing the exhaust temperature to rise and detonate any unburnt fuel.
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What does it mean when your exhaust is popping?

When combustion doesn't happen in a timely manner, the exhaust valve opens while the air-fuel mixture is still igniting, causing this explosion to “spill” out of the cylinder, making a loud popping noise. In newer vehicles, computerized sensors help ensure the air-fuel ratio is correct.
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Is it normal for your exhaust to pop?

Exhaust systems are designed to release pressure when the engine has shut down. The crackling noise is a sign that your exhaust system needs servicing, or replacement if it's not working properly. This could be caused by restrictive pipes and/or loose joints in the piping which needs tightening.
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Why does my exhaust sound like popcorn?

There are several engine components that can start making a “popping” sound when something's gone bad, including: Dirty air filter. Spark plugs that are worn or corroded. Defective spark plug wires.
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HOW TO FIX AN ENGINE BACKFIRE IN 15 MINUTES!



Can a backfire damage an engine?

An engine backfire occurs whenever the air-fuel mixture in your car combusts somewhere outside the engine's cylinders. This can cause damage to your car's exhaust or intake if left unchecked -- and it also means that your car's engine isn't making as much power as it should, and is wasting lots of fuel.
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Why do exhausts spit flames?

This phenomenon is caused by an overly-rich air/fuel mixture, as unburnt fuel is ignited further down the exhaust system, producing a loud pop or even flames from the exhaust. The spark from the spark plug can only ignite a certain amount of air/fuel mixture, therefore the excess fuel is exhausted out of the cylinder.
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Do pops and bangs damage engine?

Not only is it really obnoxious, it can potentially permanently damage your engine either quickly or slowly. If you don't know what a "Pop and Bang" tune is, let's quickly dive into what inspired it, how it came about, and where you can commonly find it.
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Why does my car sound like it's popping?

Causes of Car Popping Sounds

Spark plugs that are worn or corroded. Defective spark plug wires. Clogged fuel filter. Internal ignition wiring or related ignition issue.
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How do you fix a backfire on a deceleration?

Try setting PV to 19 and see if it improves. I have mine set at 16 right now for the same issue and that fixed it. Just keep reducing it by 1% to 16 until the popping goes away.
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Can bad spark plugs cause backfire?

Another possible cause of your backfire is a spark plug refusing to “spark” when the exhaust valve opens. If the air/fuel mixture has become too rich, unburned fuel is left in the exhaust system. The misfired spark plug ignites the rich air/fuel mixture, causing a loud “bang” in the tail pipe.
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Can fuel injector cause backfire?

On the other end of the spectrum, a bad fuel pump, vacuum leak, or clogged fuel injectors could cause an air-fuel ratio that's too lean; that is, it has too much air and not enough fuel. Though this is the opposite problem, it can also cause a backfire as vapor escapes into the exhaust and combusts there.
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Why do high performance cars backfire?

As is the case with many supercars, backfiring often occurs when the driver shifts up a gear and takes their foot off the gas pedal. This leads to a moment of rich fuel mixture reaching the engine. This fuel mixture burns incompletely, and some fuel enters the exhaust system where it burns, causing a backfire.
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Are exhaust flames illegal?

1. Exhaust flame kits. While it may sound like a great idea to have flames pouring out your exhaust pipe Fast & Furious style, it's pretty illegal in most states with many states adopting California Code 27153 as their own mandate.
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Can a stock car shoot flames?

Yes. The fast track to flame throwing is to get yourself a rotary-powered car. The reason they work so well is because they naturally run richer, meaning there's more combustible gases making their way through the exhaust system.
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Are flames bad for your car?

The first piece to wear out is that exhaust valve, which can get burned with excessive fire-spitting. If those valves can't close when fuel is ignited in the chamber, it leads to a lack of engine compression. The car's performance will drastically dip, and the engine itself won't operate properly.
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Can catalytic converter cause backfire?

A failed or damaged catalytic converter, for example, may cause small amounts of fuel to accumulate. After enough fuel has built up, heat inside the exhaust system or around the engine bay can then ignite it to create a backfire.
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Can you backfire with a cat?

As stated above (regardless of the amount of explosion) to answer in simple terms, yes a backfire can break the guts of a cat apart.
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Can a clogged fuel filter cause backfire?

A clogged air filter starves an engine of much-needed air, skewing the air/fuel mixture, which can cause an engine to backfire.
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