What Causes Backfiring and Failure to Start in a Gasoline Engine?

[DiKatherine]

Gasoline engine backfiring and failure to start can be caused by the following reasons: 1. Overly rich air-fuel mixture: An excessively rich mixture often prevents complete combustion, leading to unburned mixture being expelled through the exhaust valve and reignited by the hot exhaust manifold, resulting in backfiring. During engine operation, when unburned combustible mixture enters the exhaust pipe or muffler and encounters sparks in the exhaust or the high-temperature, high-pressure conditions of the exhaust system, it can reignite, creating a high-pressure gas surge that causes backfiring. 2. Intermittent spark plug ignition: When spark plugs misfire or fail to ignite properly, unburned combustible mixture enters the exhaust pipe and gets ignited by the high-temperature, high-pressure exhaust gases from the next combustion cycle, causing backfiring.