To fail in a manner that brings down further misfortune.
To fire in the opposite direction, for example due to an obstruction in the barrel.
To experience a premature ignition of fuel or an ignition of exhaust gases, making a popping sound.
An explosion in other equipment.
An explosion in the exhaust passages of an internal combustion engine.
A premature explosion in the cylinder of a gas or oil engine during the exhaust or the compression stroke, tending to drive the piston in the wrong direction.