Misfiring

Misfiring is the failure of a device to operate as intended, delivering an output that is absent, incomplete, or out of sequence. It is used across mechanical, electrical, and electronic systems, and can indicate a problem in design, maintenance, or operating conditions.

In firearms, a misfire occurs when the cartridge does not discharge after the firing mechanism is actuated. A hang fire is a slower-than-typical ignition following a trigger pull. Causes include weak primers, dirty or damaged cartridges, excessive moisture, or improper maintenance.

In internal combustion engines, a misfire refers to the failure of one or more cylinders to ignite the fuel-air mixture, causing rough running and power loss. Causes include worn spark plugs, faulty ignition coils, clogged fuel injectors, low fuel pressure, air leaks, or poor compression. Symptoms include rough idle, reduced acceleration, increased fuel consumption, and elevated emissions.

Diagnosis often relies on on-board diagnostics, scan tools, spark tests, compression tests, and listening for irregular firing. Prevention centers on regular maintenance, using quality components, correct air-fuel mixture, proper ignition timing, and addressing engine wear promptly.

In electrical and electronic systems, misfiring can describe a control signal or output failing to activate or occurring out of sequence, potentially due to sensor faults, wiring issues, or component degradation. Safety considerations are important in high-energy contexts, where misfires can pose risks of unintended discharge, fire, or mechanical damage.