Harnesses

Wideband Oxygen Sensor Extension Cable, 4' Features: For Holley EFI 4 ft. Extension cable for O2 sensor Use with Holley part numbers 554-100 and 554-101 Specs: Brand: Holley EFI Category: Emission Control Color: Black Connector Quantity: 2 ...

An EFI system depends heavily on being supplied a clean and constant voltage source. The grounds of an electrical system are just as important as the power side. Our Holley EFI Harness Kit comes complete with the main harness, power harness and in...

This harness provides a plug and play upgrade solution for those seeking to convert to Coil-On-Plug. Additionally we have pre-installed a Power Tap for easy access to 12v, 5v Reference, and Sensor Grounds.Features: Built in C-O-P Harness Additiona...

Universal Ford V8 Harness Kit for Holley HP and Dominator ECU'sFeatures: Harness Kit Includes: Main Power Harness, Universal MPFI Main Harness, Ford V-8 Injector Harness, Ignition Adapter & Tach Input Simple Installation Can be used with HP or...

15' long sealed USB data cableSpecs: Brand: Holley EFI Category: Vehicles, Equipment, Tools, and Supplies Color: Black Emission Code: 5 Grade Type: Performance Harness Type: Auxiliary Length: 15ft Part Type: Computer Chip Programmer Input...

Main Engine harness intended for use with Terminator X, X Max, Terminator, HP, and Dominator ECUs when using a Terminator or Terminator Stealth style Throttle Body Injection unit on a Gen 4 58x LS engine. This harness has crank and cam sensor plug...

Main Engine harness intended for use with Terminator X, X Max, Terminator, HP, and Dominator ECUs when using a Terminator or Terminator Stealth style Throttle Body Injection unit on a Gen 3 24X LS engine. This harness has crank and cam sensor plug...

Are you tired of scouring the junkyard for stock ls coil sub harnesses? Introducing the new Holley EFI LS Coil Sub Harness. This coil sub harness is intended to be used with factory LS coils and various Holley EFI main harnesses with Coil-on-plug ...

Designed to extend your factory coil harness, allowing you to easily remote mount your LS ignition coils. These 36" long ignition coil extension harnesses are perfect for anyone wanting to remote mount their ignition coils off of the valve covers ...

j2A, j2B, j3, j4 Connector & Pin Kit - Contains connectors & pins, but no wiring. for Dominator EFISpecs: Brand: Holley EFI Category: Air and Fuel Delivery Emission Code: 5 Harness Type: Auxiliary Part Type: Fuel Injector Connector P...

The Holley EFI Injector Driver Harness comes pre-terminated with a J2B connector, for plug and play connectivity with your Dominator ECU. This harness is designed to be used with the "custom" staged injection strategy in Holley EFI V5 software. In...

HP Smart Coil ignition sub-harness. Includes a pair of coil harnesses for an 8 cylinder engine. These harnesses are similar in design to factory GM LSx coil harnesses, but plug into Holley HP Smart Coils. They plug into Holley LSx plug and play ma...

Expanding on our Transmission Control options from Holley EFI. This new harness 558-455 from Holley EFI provides plug and play transmission control for the 2009+ GM 4L60 when used with a Dominator ECU. The 2009+ GM 4L60E contains an internal turbi...

Ford 4R70W/4R75W Transmission Harness - Complete terminated harness with j4 connector to operate 1998+ Ford electronic transmissions, for Dominator EFI and Terminator X Max only!Features: Complete terminated harness with J4 connector 1998+ Ford 4R...

Ford AODE/4R70W Transmission HarnessFeatures: Plug and play fully terminated harness 1992-1997 Ford AODE/4R70W (5) connectors Unterminated loose wires Specs: Brand: Holley EFI Category: Transmission Connector Quantity: 5 Emission Code: 5 Grad...

GM GEN V LTx DBW Harness. Compatible with GM part number 12617792 (L83), and 12678223 (L86, LT1, LT4).Specs: Brand: Holley EFI Category: Electrical, Lighting and Body Emission Code: 4 Harness Application: GM, LT Harness Type: Drive-By-Wire ...

Holley EFI Pro Dash replacement harness for standalone digital dashes.Features: Direct replacement Plug and Play New connectors Unterminated sensor leads Specs: Brand: Holley EFI Category: Electrical, Lighting and Body Connector Color: Black E...

Holley EFI LS main harnesses have a MAP sensor connecter designed for use with an LS1/2 style MAP sensor. The 558-416 is an adapter harness that can be used to adapt any LS harness that uses an LS1/2 MAP sensor connection to an LS3 MAP. Also gre...

Introducing a new Holley EFI DBW Throttle Body wiring harness for the OEM (Original Equipment Manufacturer) Ford Throttle Body commonly found on 2005-2010 Mustang GT's, and the GT500. This throttle body is also supported in Holley EFI V5 software ...

Introducing Coyote Twin Independent Variable Cam Timing Control from Holley EFI! Do you have a coyote crate engine going in your dream car? Is your weekend road race warrior powered by a coyote junkyard engine with locked cams? Unlock the full pot...

The Holley EFI Dominator ECU has built in capability to control dual Drive-By-Wire Chrysler Throttle Bodies - OEM P/N 53034251ABAdditionally, this harness requires pedal assembly part number 0486 1714.Specs: Brand: Holley EFI Category: Air and F...

The Holley Dominator ECU has built in capability to control the Drive-By-Wire throttle pedals and throttle bodies used on most Chrysler HEMI applications.Specs: Brand: Holley EFI Category: Ignition Emission Code: 4 Harness Application: HEMI H...

An EFI system depends heavily on being supplied a clean and constant voltage source. The grounds of an electrical system are just as important as the power side. Our Holley EFI Harness Kit comes complete with the main harness, power harness and in...

Plug and play Holley EFI alternator harnesses for late model engines with Pulse Width Modulated alternators. This includes most 2007+ GM engines and most 2005+ Ford engines.Features: Plug and play with Holley EFI and Terminator X main harnesses 20...