Holley HP EFI ECU and Harness Kits

4.44 out of 5 stars 25 Customer Reviews

Holley HP EFI ECU and harness kits allow you to manage automotive functions—like the fuel and ignition of your engine, along with controlling nitrous, boost, or wat

Holley HP EFI ECU and harness kits allow you to manage automotive functions—like the fuel and ignition of your engine, along with controlling nitrous, boost, or water/methanol. Select the model with options needed for your vehicle application. (Note: some models are engine-specific.)

Features and notes:

* Eight sequentially driven 8:2 peak and hold injector drivers capable of driving up to 16 low or high-impedance injectors are standard
* 8-channel distributorless ignition (DIS) outputs capable of directly driving "smart" ignition coils or Holley DIS coils
* Integrated, single-channel wideband oxygen sensor control. Works with NTK or Bosch sensors. More channels can be added via CAN bus.
* Internal data-logging is standard, with a huge 2GB of memory
* 4-stage progressive nitrous control
* Turbo boost control
* Integrated water/methanol injection control
* Self-tuning fuel table strategy greatly simplifies tuning process
* Individual cylinder fuel and spark control allow you to unlock your engine's potential
* Compatible with 4, 6, and 8-cylinder engines
* Unique lbs./hr.-based fueling strategy greatly simplifies tuning
* Advanced idle, closed loop, and enrichment strategies allow for very stable operation
* Fully potted and can be mounted in the engine compartment or interior
* Sealed automotive and marine-grade connectors
* Allows for use of common OEM sensors, as well as customer sensor calibration input
* Ignition plug-and-play with GM 24x and 58x LSx engines, GM HEI, Ford TFI, magnetic, and hall effect trigger, and other ignition systems
* 1-5 bar MAP sensor capability
* 2-channel knock control sensor inputs for both one and 2-wire knock sensors
* Dedicated fuel and oil pressure inputs
* Control both stepper and PWM idle air control (IAC) motors
* Speed density, Alpha-N, or combination fueling strategies
* Four programmable high or low pulse width modulated (PWM) outputs and four fully configurable inputs can be configured for use
* Lean or rich safety cutoff

Showing In Stock Items. Show All 22 Items.

Results 1 - 18 of 18

Holley HP EFI ECU and Harness Kits 554-113

Engine Management Systems, HP EFI, ECU, Replacement, Plug-and-Play, 16-Injectors, Eight Coils, Analog Inputs, USB Cable, Software, Each

Part Number: HLY-554-113

3.83 out of 5 stars ( 6 )

Estimated Ship Date: Tomorrow

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Holley HP EFI ECU and Harness Kits 550-603N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, NKT O2, GM, LS2, LS7, 58x Crank Sensor, Kit

Part Number: HLY-550-603N

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Holley HP EFI ECU and Harness Kits 550-604

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, Wideband, CANBUS, Universal, MPFI, Kit

Part Number: HLY-550-604

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Holley HP EFI ECU and Harness Kits 550-606N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, NTK O2, Wideband, CANBUS, Ford, Multi-Point, Kit

Part Number: HLY-550-606N

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-601

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, for GM TPI, Holley Stealth Ram, Kit

Part Number: HLY-550-601

4.86 out of 5 stars ( 7 )

Estimated Ship Date: Tomorrow

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Holley HP EFI ECU and Harness Kits 550-602

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, Wideband, CANBUS, Chevy, LS, 5.7L, Kit

Part Number: HLY-550-602

4.83 out of 5 stars ( 6 )

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-603

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, GM, LS2, LS7, 58x Crank Sensor, Kit

Part Number: HLY-550-603

4.5 out of 5 stars ( 2 )

Estimated Ship Date: Tomorrow

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Holley HP EFI ECU and Harness Kits 550-605N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, NTK O2, Wideband, Universal, Un-terminated, Kit

Part Number: HLY-550-605N

Not Yet Reviewed

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-605

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, Wideband, CANBUS, Universal, Un-terminated, Kit

Part Number: HLY-550-605

Not Yet Reviewed

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits for 1999-2004 MUSTANG - 550-617

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Bosch O2 Sensor, Wideband, CANBUS, Ford, 4-valve, 4.6L, 5.4L, Kit

Part Number: HLY-550-617

1.0 out of 5 stars ( 1 )

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-616

Engine Management Systems, HP EFI, ECU and Harness, Connects 16-Injectors, 8-Coils, Bosch O2, Wideband, Ford, Lincoln, Mercury, 2V, 4.6L, 5.4L, Kit

Part Number: HLY-550-616

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-628N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, NTK O2 Sensor, Wideband, CANBUS, Ford, 4.6L, Kit

Part Number: HLY-550-628N

Not Yet Reviewed

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-602N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, NKT O2 Sensor, GM, LS, 24x Crank Sensor, Kit

Part Number: HLY-550-602N

Not Yet Reviewed

Estimated Ship Date: Tomorrow

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Holley HP EFI ECU and Harness Kits 550-604N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, NTK O2, Wideband, CANBUS, Universal, MPFI, Kit

Part Number: HLY-550-604N

Not Yet Reviewed

Estimated Ship Date: Feb 13, 2026 if ordered today

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Estimated Ship Date: Feb 13, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-607

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, Wideband, GM, LS2, LS3, LS7, Bosch O2, Kit

Part Number: HLY-550-607

Not Yet Reviewed

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits for 2015-2017 F-150, 2016-2017 MUSTANG - 550-619N

Engine Management Systems, HP EFI, ECU and Harness Up to 16-Injectors, 8-Coils, NTK O2 Sensor, Wideband, CANBUS, Ford, 4-valve, 5.0L, Kit

Part Number: HLY-550-619N

Not Yet Reviewed

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-625N

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, NTK O2 Sensor, Wideband, CANBUS, Ford, 4-valve, 5.0L, Kit

Part Number: HLY-550-625N

Not Yet Reviewed

Estimated Ship Date: Feb 11, 2026 if ordered today

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Estimated Ship Date: Feb 11, 2026 if ordered today

Holley HP EFI ECU and Harness Kits 550-606

Engine Management Systems, HP EFI, ECU and Harness, Up to 16-Injectors, 8-Coils, Four Digital Inputs, Wideband, CANBUS, Ford, Multi-Point, Kit

Part Number: HLY-550-606

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Feb 12, 2026 if ordered today

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Estimated Ship Date: Feb 12, 2026 if ordered today

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