Firing order
From WOI Encyclopedia Italia
The firing order is the sequence of sparking of the spark plugs in a reciprocating engine, or the sequence of fuel injection in each cylinder in a Diesel engine. Choosing an appropriate firing order is critical to minimizing vibration and achieving smooth running, for long engine fatigue life and user comfort.
In a straight engine the spark plugs (and cylinders) are numbered, starting with #1, from the front of the engine to the rear. In most cars the front of the engine also points to the front of the car, but some manufacturers (Saab, Citroën) in some models place the engine 'backwards', with #1 towards the firewall.
In a V engine the right bank is numbered first, followed by the left bank.
In a radial engine the cylinders are numbered around the circle, with the #1 cylinder at the top. There are almost always an odd number of cylinders, as this allows for a constant every-other-piston firing order: for example, with a single bank of 7 cylinders, the order would be ...2-4-6-1-3-5-7-2....
The numbers are usually cast on the cylinder head or the intake manifold or the valve cover(s).
In a conventional engine, the correct firing order is obtained by the correct placement of the spark plug wires on the distributor. In a modern engine with an engine management system and direct ignition, the Electronic Control Unit (ECU) takes care of the correct firing sequence.
These are some usual firing orders:
| Number of cylinders | Firing order | Example |
|---|---|---|
| 3 | 1-3-2 | Saab two-stroke engine |
| 4 | 1-3-4-2 | Ford Taunus V4 engine |
| 5 | Volvo 850 | |
| 6 | 1-5-3-6-2-4 1-6-5-4-3-2 | [eep CJ 1949-1986 GM 3800 engine#231 engine |
| 7 (radial) | 1-3-5-7-2-4-6 | |
| 8 | 1-8-4-3-6-5-7-2 | 1988 Chrysler Fifth Avenue |
| 10 | Dodge Viper | |
| 12 | 1-7-5-11-3-9-6-12-2-8-4-10 | 2001 Ferrari 456M GT |
| 16 | 1-12-8-11-7-14-5-16-4-15-3-10-6-9-2-13 | Cadillac V16 engine |
See also
| Articles relating to Automobile configurations | |
|---|---|
| Car body style and classification | 2 plus 2 | Antique car | Cabrio coach | Cabriolet | City car | Classic car | Compact car | Compact performance car | Compact SUV | Convertible | Coupé | Coupé convertible | Coupe Utility | Crossover SUV | Custom car | Drophead coupe | Fastback | Full-size car | Grand tourer | Hardtop | Hatchback | Hot hatch | Hot rod | Large family car | Leisure activity vehicle | Liftback | Limousine | Luxury car | Microcar | Mid-size car | Mini SUV | Minivan | Multi-purpose vehicle | Muscle car | Notchback | Personal luxury car | Pickup truck | Retractable hardtop | Roadster | Sedan | Saloon | Small family car | Sport compact | Sports car | Sport utility vehicle | Spyder | Station wagon | Estate car | Supermini | Targa top | Taxicab | Touring car | Town car | T-top | Ute | Van | Voiturette |
| Specialised vehicles | Gyrocar | Flying car. Amphibious vehicle |
| Fuel technologies | Internal combustion engine | Electric vehicle | Neighborhood electric vehicle | Hybrid vehicle | Battery electric vehicle | Hydrogen vehicle | Fuel cell | Plug-in hybrid electric vehicle | Steam car | Alternative fuel cars | Biodiesel | Gasohol | Ethanol | LPG (Propane) | Homogeneous Charge Compression Ignition | Liquid Nitrogen | Gasoline Direct Injection |
| Driven wheels | Four-wheel drive | Front-wheel drive | Rear-wheel drive | All-wheel drive | Two-wheel drive |
| Engine positioning | Front engine | Rear engine | Mid engine |
| Layout | FF layout | FR layout | MR layout | MF layout | RR layout |
| Engine configuration | Internal combustion engine | Straight-6 | V engine | Wankel engine | Reciprocating engine | Inline engine | Flat engine | Flathead engine | Diesel engine | Two-stroke cycle | Four-stroke cycle | Pushrod engine | Straight engine | H engine | Turbodiesel | Hybrid vehicle | Rechargeable energy storage system | Electric vehicle | Hydrogen vehicle |
| Body | Framework | A-pillar | Bumper | Cabrio coach | Chassis | Crumple zone | Body-on-frame | Dagmar bumpers | Fender | Fender skirts | Grille | Hood | Hood scoop | Monocoque construction | Pontoon fenders | Quarter panel | Shaker scoop | Spoiler | Subframe | Tonneau |
| Doors | Butterfly doors | Gull-wing door | Scissor doors | Suicide door | |
| Glass | Sunroof | Greenhouse | Windshield | |
| Other | Antenna ball | Hood ornament | Japan Black paint | Nerf bar | Truck accessory | Bumper sticker | |
| Exterior Equipment | Lighting | Daytime running lamp | Headlamp | Headlight styling | Hidden headlamps | Retroreflector | Sealed beam | Trafficators | High intensity discharge |
| Other | British car number plates | Distance sensor | US and Canadian license plates | Vanity plate | Vehicle registration plate | Windscreen wiper | Windshield washer fluid | |
| Car engine | Air/Fuel | Air filter | Automatic Performance Control | Blowoff valve | Boost | Boost controller | Butterfly valve | Carburetor | Charge cooler | Centrifugal type supercharger | Cold air intake | Engine management system | Engine Control Unit | Forced induction | Front mounted intercooler | Fuel filter | Fuel injection | Fuel pump | Fuel tank | Gasoline direct injection | Indirect injection | Intake | Intercooler | Manifold | Manifold vacuum | Mass flow sensor | Naturally-aspirated engine | Ram-air intake | Scroll-type supercharger | Short ram air intake | Supercharger | Throttle body | Top mounted intercooler | Turbocharger | Turbocharged Direct Injection | Twin-turbo | Variable Length Intake Manifold | Variable geometry turbocharger. Warm air intake |
| Exhaust | Catalytic converter | Emissions control devices | Exhaust pipe | Exhaust system | Glasspack | Muffler | Oxygen sensor | |
| Cooling | Aircooling | Antifreeze | Ethylene glycol | Radiator | Thermostat | |
| Ignition system | Starter | Car battery | Contact breaker | Distributor | Electrical ballast | Ignition coil | Lead-acid battery | Magneto | Spark-ignition | Spark plug | |
| Other | Balance shaft | Block heater | Crank. Cam | Camshaft | Connecting rod | Combustion chamber | Crank pin | Crankshaft | Crossflow cylinder head | Crossplane | Desmodromic valve | Engine knocking | Compression ratio | Crank sensor | Cylinder | Cylinder bank | Cylinder block | Cylinder head | Cylinder head porting | Dump valve,Engine balance | Oil filter | Firing order | Freeze plug | Gasket | Head gasket | Hypereutectic piston | Hydrolock | Lean burn | Main bearing | Motor oil | Multi-valve | Oil sludge | Overhead camshaft | Overhead valve | PCV valve | Piston | Piston ring | Pneumatic valve gear | Poppet valve | Power band | Redline | Reverse-flow cylinder head | Rocker arm | Seal | Sleeve valve | Starter ring gear | Synthetic oil | Tappet | Timing belt | Timing mark | Top dead centre | Underdrive pulleys | Valve float | Variable valve timing | |
| Interior equipment | Instruments | Backup camera | Boost gauge | Buzzer | Car computer | Carputer | Check Engine light | Fuel gauge | Global Positioning System | Idiot light | Navigation system | Odometer | Speedometer | Tachometer | Trip computer |
| Controls | Bowden cable | Cruise control | Electronic throttle control | Hand brake | Manettino dial | Steering wheel | Throttle | Gear stick | |
| Motor vehicle theft deterrence | Car alarm | ESITrack | Immobiliser | Klaxon | Vehicle tracking system | VIN etching | |
| Passenger safety & seating | Airbag | Armrest | Automatic seatbelt | Bench seat | Bucket seat | Child safety lock | Dicky seat | Passive safety | Rumble seat | Seat belt | |
| Other | Air conditioning | Ancillary power | Car audio | Car phone | Center console | Dashboard | Motorola connector | Power window | Rear-view mirror | TripSense | |
| Powertrain | Wheels and Tires | All-terrain tyre | Bias-ply tire | Contact patch | Custom wheel | Drive wheel | Hubcap | Magnesium alloy wheel | Mud-terrain tyre | Paddle tires | Radial tire | Rostyle wheel | Run flat tires | Schrader valve | Slick tire | Spinner | Tire code | Tread | Treadwear rating | Whitewall tire | Wire wheels |
| Transmission | Automatic transmission | Clutch | Continuously variable transmission | Differential | Driveshaft | Electrorheological clutch | Epicyclic gearing | Fluid coupling | Fully-automatic transmission | Gear stick | Gearbox | Hydramatic | Limited slip differential | Locking differential | Manual transmission | Roto Hydramatic | Saxomat | Semi-automatic transmission | Semi-automatic transmission | Super Turbine 300 | Tiptronic Torque converter | Transmission (mechanics) | Transmission Control Unit | Turbo-Hydramatic | Universal joint | |
| Steering | Ackermann steering geometry | Anti-lock braking system | Camber angle | Car handling | Caster angle | Oversteer | Power steering | Rack and pinion | Toe angle | Torque steering | Understeer | |
| Suspension | Axle | Beam axle | Coil spring | De Dion tube | Double wishbone | Electronic Stability Control | Hydragas | Hydrolastic | Hydropneumatic suspension | Independent suspension | Kingpin | Leaf spring | Live axle | MacPherson strut | Multi-link suspension | Panhard rod | Semi-trailing arm suspension | Shock absorber | Sway bar | Swing axle | Torsion beam suspension | Transaxle | Trailing arm | Unsprung weight | Watt's linkage | Wishbone suspension | |
| Brakes | Anti-lock braking system | Disc brake | Drum brake | Hand brake | Hydraulic brake | Inboard brake | Brake lining | Brake fade | Brake fluid | Hydraulic fluid | Brake bleeding | Engine braking | Electronic brakeforce distribution | Regenerative brake |
