New Arrivals/Restock

Allows the most flexibility for custom applications. This harness has the custom builder in mind who wants the flexibility to run custom length wire and terminate after achieving perfect fit and finish for the vehicle.
ECU Wiring Harness
FAST offers several main harness options to accommodate most customers' needs. The XFI Main Harness is responsible for connecting your XFI ECU to sensors as well as digital dashes, EGT modules, and various optional accessories. The Main Harness also handles communication between the ECU and ignition devices. Main harnesses are available in TPI, LT-1, LS-1 through 9 (including truck/suv designs), Modern Hemi, Carburetor Conversions and even Rear-Engine Dragsters and Boats. FAST also offers Main Harnesses that come terminated on the sensor side but non-terminated on the ECU side to allow for a truely custom fit. All terminals, seals and connectors are available individually, so don't hesitate to try your hand at crafting your own custom harness from start to finish.
FAST XFI Main Harness designed for integration with Weatherpack style sensors.
Fuel Management Wiring Harness
XFI Main harness designed for a custom car builder, resto-modder or for any enthusiast who wants to take all the slack out of the harness and install an XFI fuel injection system in the cleanest way possible.
XFI Main Harness Universal