Real Dictionary

backfire
verb: If a plan or project backfires, it has the opposite result to the one that was intended.
verb: When a motor vehicle or its engine backfires, it produces an explosion in the exhaust pipe.

backfire in American English
a fire started to stop an advancing prairie fire or forest fire by creating a burned area in its path
to use or set a backfire
intransitive verb: to have a loud, premature explosion in the intake manifold
noun: premature ignition of fuel in the intake manifold

backfire in Automotive Engineering
verb: When a vehicle or its engine backfires, it produces an explosion in the exhaust pipe.

backfire in British English
(of an internal-combustion engine) to emit a loud noise as a result of an explosion in the inlet manifold or exhaust system
noun: an explosion of unburnt gases in the exhaust system