For driving enthusiasts, backfiring is cool. We hear the pops and see the flames spit from race car exhausts, and we love the aggressive sound when our own cars do it. But like so much that looks and sounds cool, it’s not healthy in copious amounts. Although modern engine control systems alleviate most of it, there are things you can do to prevent your car from backfiring.
Change oxygen sensors. It’s not a terribly frequent part to change, but it can help prevent backfiring when a fresh one (or two, as some cars require) is on board, since they detect the oxygen level in the fuel system and relay that intel to the engine control unit. If your car has over 75,000 miles or so, it’s probably about that time anyway. Even if this alone doesn’t cure backfiring, your engine will run more efficiently and mileage can improve.
Stop air leaks. Assuming parts like your idle air control valve and mass airflow sensor are functioning properly, look for frayed, unattached or missing vacuum hoses. With a bit of tracing, they’re usually accessible and simple to remedy. It’s an inexpensive but effective fix.
Renew that spark. Our dads and granddads had to check and clean spark plugs almost as often as they mowed lawn. We have it easier, but don’t overlook changing the plugs and plug wires when needed to prevent backfiring. Consult your owner’s manual for replacement interval, and watch for anything other than normal wear on the spark plug tips.
Check engine belts. Depending on your car, you may have multiple belts at the front of the engine or just a single serpentine belt for multiple components. Regardless, belts wear and tension loosens as miles accumulate. This can throw off your timing, and your engine control unit may not be able to fully compensate for it.
Keep a healthy exhaust. The most noticeable backfiring happens in the exhaust system, where the catalytic converter lives a hard life even under normal circumstances. Backfiring can be a clue that the cat con isn’t functioning properly or could be nearing the end of its service.