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Holley EFI Systems Wiring Harnesses

4.77 out of 5 stars 31 Customer Reviews

Holley offers a variety of direct replacement EFI wiring harnesses, including multi-port, sequential, and throttle body injection styles. These units are made with premium components to ensure better reliability and performance for your ride--and they're compatible with many engine swaps. Holley EFI systems wiring harnesses are sold individually or as a kit; choose the model needed for your fuel injection application.

Results 1 - 25 of 31

Fuel Injection Systems Wiring Harnesses, Holley EFI, Drive-by-Wire Harness, GM LSx, for Dominator EFI Systems, 6-Pin, Each

Part Number: HLY-558-406

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Wiring Harnesses, Holley EFI, Replacement, LS1/6, 24X/1X Main Harness, Mass Airflow Metered, for HP, Dominator, EFI Systems Only, Chevy, 5.7L, Each

Part Number: HLY-558-102

5.0 out of 5 stars ( 4 )

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Wiring Harnesses, Holley EFI, Replacement, LS Style, 58X/4X Main Harness, Speed Density, for HP, Dominator, EFI Systems Only, Chevy, 6.0-7.0L, Each

Part Number: HLY-558-103

5.0 out of 5 stars ( 1 )

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Wiring Harness, Holley EFI, V8 Over Manifold, Bosch Injector Harness, for Avenger, Dominator, HP EFI Systems, Chrysler, GM, Cylinder Orientation, Kit

Part Number: HLY-558-200

5.0 out of 5 stars ( 3 )

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Wiring Harnesses, Holley EFI, Replacement, Main Harness, Multi-port Fuel Injection, for HP, Dominator, EFI Systems, Universal, Each

Part Number: HLY-558-104

4.0 out of 5 stars ( 2 )

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Fuel Injection System Wiring Harnesses, Holley EFI, Multi-port Fuel Injection, Coil-on-Plug, Dual CANbus, for Holley HP, Dominator EFI, Universal, Kit

Part Number: HLY-558-117

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Fuel Injection System Wiring Harnesses, Holley EFI, Drive-by-wire Harness, GM LSx Early Truck, MPFI, SFI, TBI, for Dominator EFI Systems, Each

Part Number: HLY-558-429

4.67 out of 5 stars ( 3 )

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Fuel Injection System Wiring Harnesses, Holley EFI, Fuel Injector Harness, Unterminated, Bosch Style, for HP, Dominator EFI Systems, Universal, Each

Part Number: HLY-558-204

3.0 out of 5 stars ( 1 )

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Fuel Injection System Wiring Harnesses, Dominator EFI, GM LSx, Dual Drive-by-Wire Harness, for Throttle Bodies to Dominator EFI Systems, Each

Part Number: HLY-558-411

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Fuel Injection System Wiring Harnesses, Holley EFI, GM LS 58X Crank Sensor, Power, Bosch Injector, Main Harnesses, for HP, Dominator ECUs, Kit

Part Number: HLY-558-502

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Wiring Harnesses, Holley EFI, Main Harness, 24X LS TBI, for Terminator, Terminator Stealth, Throttle Body Systems, Chevy, Each

Part Number: HLY-558-111

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Wiring Harnesses, Holley EFI, Ford 2V/4V Modular, Main Harness, Multi-Port Fuel Injection, for Holley Smart Coils, HP EFI System, Ford, 4.6-5.4L, Each

Part Number: HLY-558-113

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Fuel Injection System Wiring Harnesses, Holley EFI, Universal, V8 MPFI Harness, with Main, Power, Bosch Injector Harnesses, for HP, Dominator ECU, Kit

Part Number: HLY-558-504

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Wiring Harnesses, Holley EFI, Ford 2V/4V Modular, Main Harness, Multi-port Fuel Injection, for HP, Dominator, EFI Systems, Ford, 4.6-5.4L, Each

Part Number: HLY-558-108

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Estimated Ship Date: Aug 22, 2025 if ordered today

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Estimated Ship Date: Aug 22, 2025 if ordered today

Fuel Injection System Wiring Harnesses, Holley EFI, 6 Cylinder, MPFI, SFI, TBI, Injector Harness, for HP, Dominator EFI Systems, Universal, Each

Part Number: HLY-558-203

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Fuel Injection System Wiring Harnesses, Holley EFI, Terminator, Throttle Body Systems, Plug-and-Play, Upgrade Harness, for 205 lb./hr. Injectors, Each

Part Number: HLY-558-439

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Wiring Harnesses, Holley EFI, Replacement Harness, Multi-Port, Speed Density Metered, for Avenger, HP, Dominator, EFI Systems, with Stealth Ram, Each

Part Number: HLY-558-101

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Wiring Harnesses, Holley EFI, Gen III Hemi, Throttle Position, Idle Air Controls, Factory Connectors, Chrysler, Dodge, Jeep, Hemi, Early Model, Each

Part Number: HLY-558-115

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Estimated Ship Date: Aug 22, 2025 if ordered today

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Estimated Ship Date: Aug 22, 2025 if ordered today

Fuel Injection System Wiring Harnesses, Holley EFI, Ford V8, Universal MPFI, with Main, Power, Injector Harnesses, for HP, Dominator ECU, Kit

Part Number: HLY-558-508

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Estimated Ship Date: Aug 21, 2025 if ordered today

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Estimated Ship Date: Aug 21, 2025 if ordered today

Fuel Injection System Wiring Harnesses, Holley EFI, Replacement, Main Harness, Terminator EFI Systems, Model 550-405, 550-406, Each

Part Number: HLY-558-414

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Wiring Harnesses, Holley EFI, Main Harness, 58X LS TBI, for Terminator, Terminator Stealth, Throttle Body Systems, Chevy, Each

Part Number: HLY-558-112

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Wiring Harnesses, Holley EFI, Gen III Hemi, Throttle Position, Idle Air Controls, Factory Connectors, Chrysler, Dodge, Jeep, Hemi, Late Model, Each

Part Number: HLY-558-116

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Fuel Injection System Wiring Harnesses, Holley EFI, Crank/Cam Ignition Harness, Plug-and-Play, for Ferrous Hall Effect to HP/Dominator Systems, Each

Part Number: HLY-558-431

4.8 out of 5 stars ( 5 )

Estimated Ship Date: Today

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Fuel Injection System Wiring Harnesses, Holley EFI, Unterminated, Ignition Harness, with Pins, Seals, Connector, for HP, Dominator EFI Systems, Kit

Part Number: HLY-558-306

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Wiring Harnesses, Holley EFI, TFI Ignition, Adapter Harness, for Avenger, HP, Dominator EFI Systems, Each

Part Number: HLY-558-305

4.9 out of 5 stars ( 10 )

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