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Description
Holley HP EFI ECU and Harness Kits 550-604NHP ECU AND HARNESS, MPFI, NTK Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine
HP ECU AND HARNESS, MPFI, NTK
Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine along with additional controls for nitrous, boost or water meth.
Features:
- Optional 5.7” full-color touchscreen LCD allows easy on-the-fly tuning, data-logging or can be used as an easy to see graphical gauge panel
- Eight sequentially driven 8:2 peak and hold injector drivers, capable of driving up to 16 low or high impedance injectors as a standard feature. Multiple staged injector strategies
- Eight channel Distributorless Ignition (DIS)outputs capable of directly driving “Smart” ignition coils or Holley DIS coils. Will drive 2 wire coils with the addition of PN 554-112 high current coil driver module
- Integrated single channel wide band oxygen sensor control. Works with NTK or Bosch sensors
- Internal data-logging 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 allows you to unlock your engine’s potential
- Works with 4, 6, 8 cylinder engines
- Unique lb/hr based fueling strategy greatly simplifies and commonizes tuning
- Advanced idle, closed loop, and enrichment strategies allow for very stable operation
- ECU is 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 HEI, Ford TFI, magnetic and hall effect trigger, and other ignition systems. New Plug and Play applications in process. Custom settings can be configured to allow many other applications
- 1-5 Bar MAP sensor capability
- Two channel knock control sensor Inputs for both one or two wire knock sensors
- Dedicated fuel and oil pressure inputs
- Controls both stepper and PWM Idle Air Control (IAC) motors
- Speed density, Alpha-N, or combination fueling strategies
- 4 Programmable high or low Pulse Width Modulated (PWM) outputs and 4 fully configurable inputs can be configured for use
- 4 Stage nitrous oxide control
- Fully featured nitrous control eliminates the need for a separate nitrous controller device
- Can be configured “Wet” or “Dry” with closed loop feedback
- Progressive control based on time, RPM, or boost, requires part # 554-111
- Lean or rich safety cutoff
- Full timing retard/control configurability per stage based on RPM or time
- Integrated Water/Methanol injection control
- Uses Holley Water/Meth solenoids specially designed and calibrated for use with this EFI system to allow the user to enter Water/Meth flow as a percentage of fuel injector flow for Water/Meth tuning precision unmatched in the industry
Application
- Universal
Specs
| Brand | Holley EFI |
|---|---|
| Emission Code | 3 |
| Ignition Type | Coil - (No Timing Control) |
| Ford TFI | |
| GM HEI Small Cap | |
| Holley Dual Sync Distributor | |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | HP EFI Kit |
| Part Number | 550-604N |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.5 ★★★★★
Based on 2186 reviews
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Product Reviews
★★★★★ 5
Quedo bien para pontiac vibe 2003
Buena calidad aunque no vienen en par, asi que si necesitas 2 tendras que hacer 2 pedidos
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 9, 2025
★★★★★ 2
Lights
They don't fit 2016 Chevrolet Silverado
But they arrived quick .
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Reviewed in the United States on February 18, 2026
★★★★★ 5
Effective
Size: 300 Milliliter
This worked wonders on my car’s performance! After one use, the engine started idling much smoother and the throttle feels more responsive. A very high-quality German-made product.
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Reviewed in the United States on April 24, 2026
★★★★★ 5
Great for All Cars but Especially German Cars
Size: 300 Milliliter
I use this in our used VW we bought and it helps keep the carbon build up down with their direct injection feature. I pair it with their oil additive which helps lubricate the rings so they don't stick as much.
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Reviewed in the United States on May 22, 2026
★★★★★ 5
Significant Improvement in Performance with Liqui Moly Jectron
Size: 300 Milliliter
I've been using the Liqui Moly 2007 Jectron Gasoline Fuel Injection Cleaner in my vehicle, and I am thoroughly impressed with the results. The 300 ml bottle, though compact, has made a noticeable difference in the performance of my car.
After adding the Jectron cleaner to my gasoline tank, I noticed an improvement in the engine's responsiveness and smoothness within just a few drives. The idling has become steadier, and the acceleration feels more robust and refined. It's as if my car has regained a level of vitality that I hadn't realized was missing.
The cleaner is incredibly easy to use – simply pouring it into the fuel tank before filling up ensures it mixes well and distributes evenly throughout the fuel system. I appreciate that this product is designed to be compatible with all gasoline engines, making it a versatile choice for different types of vehicles.
One of the most significant benefits I've observed is the reduction in start-up problems and engine hesitation. It's clear that the Jectron cleaner effectively cleans the fuel injectors, improving fuel atomization and combustion efficiency. This has not only enhanced the driving experience but also contributed to better fuel economy, which is a fantastic bonus given current fuel prices.
The blue color of the liquid and the design of the bottle make it easy to identify and use, ensuring I don't mix it up with other products. Despite being a single 10.14 Fl Oz pack, this cleaner packs a punch, proving that a little goes a long way.
In conclusion, the Liqui Moly 2007 Jectron Gasoline Fuel Injection Cleaner has exceeded my expectations. It has revitalized my car's engine, improved fuel efficiency, and provided a smoother, more enjoyable driving experience. I highly recommend this product to anyone looking to enhance their vehicle's performance and maintain the health of their fuel injection system.
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Reviewed in the United States on February 18, 2024