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Sequential-port Fuel Injection (SPFI)

A type of multi-port injection system where individual fuel injectors are pulsed sequentially, one after another in the same firing order as the spark plugs, rather than being pulsed simultaneously. This allows more precise fuel control for lower emissions and better performance. Also known as sequential fuel injection.

Sequentially Fired

A type of fuel-delivery system in which the fuel injectors are fired individually according to ignition firing order and valve timing.

Serial Data

The pulse train data signal sent on the communication line between the computer and the scan tool.

Series Circuit

A circuit having only one path through which the current or fluid can flow, having to pass through one component before going on to another.

Series Number

A term used for tire aspect ratio.

Series Parallel Circuit

A circuit in which some components are in series while others are in parallel.

Series Parallel System

An arrangement where two 12-volt batteries are connected in such a manner as to provide 24-volts for starting and 12-volts for accessories and charging.

Series Wound

In a starter motor, the field coils (windings) and the armature, are wired in series. All current flows through the field coils, through the hot brushes, through the armature, then to the ground through the ground brushes.

Serpentine Belt

A wide, flat belt having multi-V-grooves to provide friction contact with the pulleys that winds through all of the engine accessories to drive them off the crankshaft pulley.

Serrated Nut

A self-locking type of nut having serrations on its contact side to prevent it from loosening when tightened.

Serrated Rod Cap

A connecting rod cap that has serrated parting edges to help maintain alignment with the rod.

Service Assess Gauge-port Valve

Fittings found on some service valves and some control devices used to access the system for testing and service.

Service Bay Diagnosis System

SBDS A computerized information network system that is connected, often by satellite, to the vehicle manufacturer and used to answer service and diagnostic questions.

Service Bulletin

Technical service information provided by the manufacturer, used as updates for the service manuals and to provide the latest service tips, field repairs, product information, and other related information for the service technician.

Service Engine Light

Light used to inform the driver of a malfunction in the computer control system.

Service Hose

A hose that attaches a test gauge set to the service fitting of a system.

Service Manager

The person who is generally responsible for the entire service operation of a dealership.

Service Manual

A manual provided by the manufacturer or other publisher that describes service procedures, troubleshooting and diagnosis, and specifications for a particular car line.

Service Port

An access fitting found on the service valve and some control devices that the gauge set hoses are connected to for service and testing.

Service Procedures

A recommended step-by-step procedure to follow to troubleshoot, disassemble, assemble, or repair an automotive system or component.