DIY Auto Blog

Precautionary measures to stop engine backfire

June 17th, 2012

When your car backfires, not only is it annoying and embarrassing, but also it is causing damage to your engine. It is caused by excess fuel that has escaped the engine and explodes in the carburetor, exhaust system or air cleaner. The problem of backfiring is less common in newer cars, which have been designed to prevent unburnt fuel from escaping the engine. The sound of a backfire is obvious, as well as the loss of power you will more than likely experience right after. Proper maintenance of your vehicle as well as fixing problems as soon as they arise can eliminate the reasons that backfiring occurs.  There are some common reasons for backfiring that you need to watch for. Keep in mind the problem of backfiring has nearly been eliminated in newer vehicles, but if you drive an older vehicle, there are a number of causes for backfiring.

Causes of engine backfire

If you have a missing or blocked catalytic converter, you may experience backfiring. Catalytic converters play a vital role in the proper function of your engine. They remove unused hydrocarbons from exhaust gas as well as clean potential pollutants out before they reach the outside air. If the converter is gone or is not working the way it should, it allows unburnt fuel to pass through the exhaust causing an explosion in the exhaust system. Although replacing the catalytic converter is a pricey repair, it is small in comparison to having to replace an engine damaged by backfiring.  Another common issue that can cause backfiring is a vacuum leak.  The system that forces air into the exhaust is vacuum-sealed. Any compromise in this seal will negate the pressure and prevent the injection of air into the exhaust. This leads to a build-up of exhaust gases that can cause small explosions as well. Vacuum leaks can be relatively inexpensive to fix, again much cheaper than having to replace and engine because of damage caused by misfiring.

If your engine light comes on, although you may be tempted to ignore it because you vehicle seems to be running as it does normally, do not ignore it. There are many reasons that your engine light will come on, but one of the most common is a faulty oxygen sensor or sensors. Oxygen sensors measure the amount of oxygen in the fuel system and tell the engine’s computer how to produce the optimal fuel and oxygen mix in the engine. If the oxygen sensor is not working properly, it can send the wrong information to the engines computer system. This can cause a higher fuel to oxygen ratio, leading to an excess of unburnt fuel, which can again cause explosions in the engine or exhaust system. The check engine light is one of the most important lights on your dash to pay attention to, as soon as it comes on, make sure you take your vehicle in for repairs as soon as you can to prevent any additional problems or damage to your engine.

What to do to prevent engine backfire

Regular maintenance can eliminate the potential of backfiring before you even have a problem. Making sure that belts are in good working order and not loose is important as they affect engine timing. If the belt is slack, it can cause the engine to be out of rhythm and therefore will not be using fuel efficiently which can lead to backfiring.  Fuel filters and air filters should be checked periodically as well. A blocked fuel or air filter can again affect the fuel and oxygen ratio setting up ideal conditions for backfiring.  Maintaining a vehicle as well as getting any problems fixed immediately can keep you from having any problems with your vehicle.

Summary

If you try to take care of any backfiring problem yourself, but it is still occurring, it is best to let your mechanic handle it, especially with a newer car. Most backfiring problems in newer cars are computer related which require the tools and expertise that only a mechanic can provide. If you have an older car and have replaced a clogged air filter and done the small things you could to try to alleviate the problem, then it is time to take your car to a mechanic. No matter what is causing the backfiring problem, keep in mind that every time it happens it is damaging your engine. It is much easier and cheaper to fix a problem that may cause or is causing your vehicle to backfire versus replacing the entire engine.