Fuel Injection Glossary

The terms below are used throughout this website. And while you probably know what they mean in general, we thought it would be helpful to know how Holley uses these them when referring to their fuel injection kits. Is there a term or phrase you'd like to see added? Let us know!

2-Wire Coil Driver: Holley ECU's are designed to work with 4-wire coils, but a 2-wire coil driver module is available to allow you to use 2-wire coils. A 2-wire coil is simply a voltage multiplier. It takes the applied voltage and increases it to the level necessary to create a spark in the engine. The 4-wire coil adds a switch that turns the output of the coil on when 5 volts DC is applied across the second pair of wires.

Crank Trigger Mounting Kit: Includes Crank trigger wheel, brackets, and hardware for a specific application. Purchase along with a Distributorless Ignition System (DIS) to form a complete DIS kit for that specific application.

Crank Trigger System: Contains everything needed to install a crank trigger wheel system on a given application, including 60-2 Crank Trigger Wheel, sensor, mounting brackets, and harness. Note that harness includes a connector for cam sensor output, but cam sensor is not included in these kits. Kits are currently available for small block Chevy and big block Chevy. If you need a crank trigger system for other applications, these components are available individually.

Crank Trigger Wheel: A round, flat plate made of steel with notches cut into the outer circumference. This wheel is mounted at the end of the crankshaft (typically with the crank pulley.) As the crank spins, these notches pass a sensor, which, by counting the number of notches past top dead center (TDC), tells the ECU the degrees of rotation of the engine. TDC is detected by a double-wide notch. Holley crank trigger wheels have 60 notches plus one TDC double notch. They are available in a number of different sizes to support the clearances on different engines (5", 6", 7 3/4", and 8 1/2" Diameter.) Center hole is 1" diameter and may require machining for application.

Distributorless Ignition System (DIS): Available for 4-, 6-, and 8-cylinder applications. Contains coils (1 per 2 cylinders), trigger wheel sensor, and harnesses. Does not include crank trigger wheel. Purchase a crank sensor mounting kit for your specific application for an application-ready kit, or purchase a crank trigger wheel and fabricate your own brackets to create a kit for your unique application.

Drive-By-Wire (DBW) Control: Exclusively available on the Dominator ECU. This feature was added to support GM vehicles with DBW. Approved for use with GM 12570790 and 12580760 throttle bodies and 10379038 pedal assemblies.

Ignition Harness: Connects directly to the ignition connector on the main harness. Finished harnesses are available for a broad range of applications (HEI, GM LS1 or LS2, Ford TFI, and more) as well as universal coil-on-plug harnesses and unterminated ignition harnesses.

Injector Harness: Connects directly to the injector connector on the main harness. Allows you to configure any main harness to work with the most common injector type and quantities with a simple snap-in (4-Cylinder Bosch, 8-Cylinder EV6.) Optionally, select unterminated and supply your own injector connectors (up to 24 injectors.)

Main Harness: This harness carries all sensor inputs to and control outputs from the Engine Control Unit (ECU). It does not carry power and ground for the ECU (see Main Power Harness). It is meant to carry the signals from the location of the ECU (commonly in the driver compartment) to the engine compartment. The Main Harness connectors inside the engine compartment do not typically connect directly to the components there, but connect to a sub-harness for that component. This allows a single Main Harness to be customized to work with a huge combination of different injectors, ignition components, and sensors. (See Ignition Harness, Injector Harness.) The Main Harnesses included in kits are customized for that kit, and can be purchased separately for replacement. The Dominator ECU does not include a Main Harness, so it must be purchased separately. All Main Harnesses will fit all Holley ECU's.

Main Power Harness: Included with every kit or individual ECU. Not typically purchased except to replace a damaged/lost Main Power Harness.

Nitrous Solenoid Driver: Enables your HP or Dominator ECU to do progressive nitrous control. Use one driver per progressive stage (up to four stages max.) Not required for non-progressive nitrous control, but can be used as a standard relay for this purpose.

Transmission Control: Exclusively available on the Dominator ECU. With the addition of an optional harness, you can program transmission shift points (currently available for The GM 4L60/65/70/80/55E Transmissions with more on the way.) Add a paddle shifter (available through sources other than Holley) and achieve manual shifting of your automatic transmission.