The spark plugs are used as sensors to detect combustion and pre-ignition/pinging. Pingdom functions by regularly pinging websites to check whether the site is accessible to users. This sensor is normally a prerequisite for a sequential pre ignition/pinging regulation and fuel injection. This usually entails pinging or polling the component and waiting to receive a response. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. This helps to prevent pre-ignition (or pinging). The bell produces a higher "pinging" pitch than the rest of the cymbal. Ejection of an empty clip created a distinctive metallic "pinging" sound. And the cell phone stopped pinging the tower at about 8 am 28 May 2011. Many silent calls are a result of process known as pinging. As she reloaded, the enemy destroyers closed in, pinging, but no depth charges came. Meanwhile, the Japanese minesweeper (Kaibokan) continued out, pinging continually, and "Hake" moved off to evade. When a level is completed, the game plays a pinging version of "Deck the Halls".