Definition of discourse marker noun from the Oxford Advanced Learner's Dictionary
When an engine starts knocking, one of the first things a mechanic will check is the oil pressure. A warning light may come on in the car, and adding sufficient oil will solve the problem. Sometimes, a knocking noise is caused by loose torque converter bolts or a loose flywheel.
Here is a list of the most common causes for pinging starting with the most popular ones. 1  Fuel octane rating too low. 2  Compression too high. (usually caused by carbon build up inside the combustion chambers) 3  Over heating of the engine or just an individual cylinder. (Hot spots)  Knock detector faulty.