What is the difference between backfire and afterfire?
2 Answers
The difference between backfire and afterfire is: backfire occurs in the intake system, while afterfire occurs in the exhaust system. The following are the causes of engine backfire: 1. Slow combustion of the air-fuel mixture. 2. Incorrect ignition sequence. 3. Low battery voltage. 4. Faulty coolant temperature sensor or air flow meter. 5. Excessive ignition advance angle (this is very important). 6. Incorrect valve timing. 7. Excessive carbon buildup on the valves. 8. Incorrect ignition sequence. 9. Faulty spark plugs. The following are the causes of engine afterfire: 1. Dirty or clogged filter. 2. Impure gasoline quality. 3. Insufficient ignition advance angle. 4. Incorrect valve timing. 5. Faulty air flow meter. 6. Insufficient spark plug breakdown voltage. 7. Incorrect ignition sequence.
Backfire and knocking in car engines really show different symptoms. I remember when backfire occurs, it sounds like popping combustions in the exhaust pipe, as if there's an issue with the ignition system—maybe aged spark plugs or incorrect air-fuel mixture causing unburned fuel to detonate in the exhaust. Knocking, on the other hand, sounds more like pistons hitting the cylinder walls internally, with a thumping noise, usually caused by loose pistons or detonation, potentially damaging piston rings. Experienced drivers know backfire often happens during cold starts, while knocking becomes noticeable at high RPMs. Don’t underestimate these noises—they’re warning signs of engine trouble. Check ignition timing or replace spark plugs promptly to prevent worse damage.
