Wiring & Plugs

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 injector...

Unterminated 16 injectors MPFI harness Terminated at injector connectors (Bosch style). Harness must be assembled and require crimping Metripak150 connectors. Includes all connectors, pins, terminals, and loom needed. for HP EFI & Dominator EFI

Terminated Vehicle Harness For Digital Dash

Main harness for 99-04 2 & 4 Valve Ford Modular (4.6 & 5.4L) Engines.

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 great for...

Main Harness for 99-04 2 & 4 Valve Ford Modular (4.6 & 5.4L) Engines for use with Holley Smart Coils

An Injector Harness is required and Holley offers two. The harness with USCAR/Stock injector connectors will cover most applications that are using the factory injectors. The other harness is for the Bosch and Holley (or Jetronic/Minitimer) injector...

This Universal 4 Cylinder EV14 Injector Harness is designed to be plug and play with HP EFI & Dominator EFI Systems, utilizing our 205 LB/HR Injector Set - Part Number 522-205.

"Big Wire" Sub Harness- pre wired with 12ga power and grounds, for optimal performance!

Gen III HEMI Harness with TPS and Idle Air Control Connections.This wiring harness interfaces a Holley EFI ECU to a Gen III HEMI engine with an aftermarket cable actuated throttle body. It is meant to be used in conjunction with an injector harness, a...

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 potential...

Drive-By-Wire harness for 2011-2017 Ford Coyote (5.0L) engines