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.
Rating Newest Oldest. Best Answer: The knock sensor is basically a microphone. Its there to listen for spark knock which is also called detonation, pinging, and pre ignition. This is the condition inside the engine where the fuel begins to burn before its supposed to. It sounds like someone rattling a can of marbles.