Automotive Glossary of Terms - F -
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W
Definitions for automotive terms and illustrations from fast idle to front wheel drive.
FAST IDLE: The speed of the engine when the choke is on. Fast idle speeds engine warm-up.
FEDERAL ENGINE: An engine certified by the EPA for use in any of the 49 states (except California).
FEELER GAUGE: A blade, usually metal, of precisely predetermined thickness, used to measure the clearance between two parts.
FILAMENT: The part of a bulb that glows; the filament creates high resistance to current flow and actually glows from the resulting heat.
FINAL DRIVE: See axle ratio.
FIRING ORDER: The order in which combustion occurs in the cylinders of an engine. Also the order in which spark is distributed to the plugs by the distributor.
FLAME FRONT: The term used to describe certain aspects of the fuel combustion in the cylinders. The flame front should move in a controlled pattern across the cylinder, rather than simply combusting immediately.
FLAT ENGINE: Engine design in which the pistons are horizontally opposed. Porsche, Subaru and some old VWs are common examples of flat engines.
FLAT RATE: A dealership term referring to the standard fee charged by a technician for a particular repair or diagnostic service versus the actual labor time.
FLAT SPOT: A point during acceleration when the engine seems to lose power for an instant.
FLOODING: The presence of too much fuel in the intake manifold and combustion chamber which prevents the air/fuel mixture from firing, thereby causing a no-start situation.
FLYWHEEL: A heavy disc of metal attached to the rear of the crankshaft. It smoothes the firing impulses of the engine and keeps the crankshaft turning during periods when no firing takes place. The starter also engages the flywheel to start the engine.
FOOT POUND (ft. lbs. or sometimes ft. lb.): The amount of energy or work needed to raise an item weighing one pound a distance of one foot.
FREEPLAY: The amount of travel in a clutch pedal or brake pedal before movement of the clutch or brakes take place. This adjustment is critical to the proper operation of the clutch or brakes.
FREEZE PLUG: A plug in the engine block which will be pushed out if the coolant freezes. Sometimes called expansion plugs, they protect the block from cracking should the coolant freeze.
FRONT END ALIGNMENT: A service to set caster, camber and toe-in to the correct specifications. This will ensure that the car steers and handles properly and that the tires wear properly.
FRONTAL AREA: The total surface area of the front of a car that is exposed to air flow.
FUEL FILTER: A component of the fuel system containing a porous paper element used to prevent any impurities from entering the engine through the fuel system. It usually takes the form of a canister-like housing, mounted in-line with the fuel hose, located anywhere on a car between the fuel tank and engine.
FUEL INJECTION: A system replacing the carburetor that sprays fuel into the cylinder through nozzles. The amount of fuel can be more precisely controlled with fuel injection.
FULL FLOATING AXLE: An axle in which the axle housing extends through the wheel giving bearing support on the outside of the housing. The front axle of a four-wheel drive car is usually a full floating axle, as are the rear axles of many larger (3/4 ton and over) pick-ups and vans.
FULL-TIME FOUR-WHEEL DRIVE: A four-wheel drive system that continuously delivers power to all four wheels. A differential between the front and rear driveshafts permits variations in axle speeds to control gear wind-up without damage.
FUSE: A protective device in a circuit which prevents circuit overload by breaking the circuit when a specific amperage is present. The device is constructed around a strip or wire of a lower amperage rating than the circuit it is designed to protect. When an amperage higher than that stamped on the fuse is present in the circuit, the strip or wire melts, opening the circuit.
FUSIBLE LINK: A piece of wire in a wiring harness that performs the same service as a fuse. If overloaded, the fusible link will melt and interrupt the circuit.
FRONT WHEEL DRIVE (FWD): Front wheel drive.