1. fires (a gun, weapon, or engine) before the intended or proper time
Usage: third person singular present tense of 'prefire'
2. ignites or activates (a device or system) in advance or prematurely
Usage: technical or specialized use

Examples

• The engine prefires when the fuel mixture is too rich.
• If the trigger mechanism is faulty, the gun may prefire unexpectedly.
• The system prefires the ignition coil to ensure proper combustion timing.
• He adjusted the carburetor to prevent the engine from prefiring.
• The weapon prefires due to a defect in the firing pin.