Pre-ignition Pre-ignition Pre-ignition (or preignition) in a spark-ignition engine is a technically different phenomenon from engine knocking, and describes the event wherein the air/fuel mixture in the cylinder ignites before the spark plug fires. Pre-ignition is initiated by an ignition source other than the spark, such as hot spots in the combustion chamber, a spark plug that runs too hot for the application, or carbonaceous deposits in the combustion chamber heated to incandescence by previous engine combustion events. The phenomenon is also referred to as 'after-run', or 'run-on' or sometimes dieseling, when it causes the engine to carry on running after
MSD Ignition MSD Ignition MSD Ignition is an American automotive aftermarket manufacturing company that specializes in high-end ignition system and electrical components. MSD Ignition was the first company in the world to experiment with Multiple Spark Discharge for the ignition system of internal combustion engines in 1970. The idea was first proposed by a group of engineers working on the White Sands Missile Range in southern New Mexico. The engineers worked for the research and development company Autotronic Controls Corporation (ACC) that was striving to develop leaner burning fuel systems to increase engine fuel efficiency. The engineers discovered that their limiting factor