Smart coil - A type of ignition coil that has its ignition drivers (IGBT) built into the coil, this means they only receive a 5v signal to activate.
SMD - Surface mount device, interchangeable with SMT
SMT - Surface mount technology, interchangeable with SMD
Stoichiometric - The ideal quantity of fuel to burn with a quantity of air for complete combustion. For gasoline this is 14.7:1, ethanol is 9:1 and methanol 6.47:1
AFR is the ratio of air to fuel, often expressed as "14.7:1"
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<details><summary><u>AIT</u></summary>
Air Intake Temperature
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<details><summary><u>Baro</u></summary>
Shorthand for Barometric pressure
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<details><summary><u>BTDC</u></summary>
Before TDC, Before Top Dead Center - See also ATDC
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<details><summary><u>CAS</u></summary>
Crank Angle Sensor Also See [CPS](http://en.wikipedia.org/wiki/Crankshaft_position_sensor)
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<details><summary><u>CLT</u></summary>
Coolant Temperature
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<details><summary><u>CPS</u></summary>
Crankshaft Position Sensor
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<details><summary><u>EDIS</u></summary>
Electronic Distributorless Ignition System - An older Ford ignition system that combined a set of ignition IGBTs and some electronics to assist the ECU. Obsolete on modern ECUs.
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<details><summary><u>EGO</u></summary>
Exhaust Gases Oxygen - see also lambda sensor, WBO2,
Often used when referring to air fuel sensors like the lambda sensor.
Sometimes also used as HEGO or Heated Exhaust Gas Oxygen.
Often this refers to Sequential injection, which means the injectors fire individually for each cylinder and often at a specific crank angle.
This can be handy for engines direct injection or to try to spray the injector into the cyl while the intake valve is open. If an engine can inject onto an open inlet valve it will reduce the amount of fuel wetting the port walls and help reduce low load emissions.
Sequential is required for direct injection engines like common rail diesel.
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<details><summary><u>SD</u></summary>
Speed Density this is a method of predicting how much fuel should be delivered to an engine. This is a MAP based system which uses pressure to make a prediction of how much O2 is entering the cyl.
The use of 2 injectors for one cyl. This commonly means at low RPM and lower loads, one injector is turned on which allows for finer control over idle fuel delivery, while at higher RPM and higher Loads both injector inject fuel which allows for larger amounts of fuel to be delivered.
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<details><summary><u>TDC</u></summary>
Top Dead Center
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<details><summary><u>TFI</u></summary>
Thick Film Ignition - Ford distributor - Likely unsupported at this time.
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<details><summary><u>VE</u></summary>
Volumetric Efficiency, often expressed as a decimal value i.e. 0.8 (for 80%)