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Ships within 48 hours · Estimated delivery Jul 11 - Jul 16
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Description
HP EFI ECU & Harness Kits - 550-601NOverview: 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
Overview:
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:
NEW V2 SOFTWARE FEATURES - “Quick Start” ignition and fueling strategy for LS x Engines
- Data Logger. Scalable axes, Smoothing, Multiple graph view ability, Pre-defined notes fields and many more
- Strip Chart Real-Time Data Viewer
- Integrated Boost Control - Boost vs Time, Boost vs Gear (Time or RPM), Boost vs RPM, Boost vs Speed, Launch control. Boost launch builder, Over-boost safeties, Boost scramble
- Traction Control - Power reduction via timing, nitrous percentage or boost (Requires Davis Technologies Holley Module)
- “Quick Start” fueling for all engines
- Option for VE based fueling strategy
- Fuel Map and Learn Function Smoothing
- Configurable User Password Protection
- Fully Configurable lap top Gauge Panel
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
- Plug and Play control of factory GM 24x and 58x LSx engines
- 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 24x and 58x LSx engines, 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:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| Universal |
Specs:
| Brand | Holley EFI |
|---|---|
| Emission Code | 3 |
| Ignition Type | Coil - (No Timing Control) |
| Ignition Type | GM HEI Small Cap |
| Ignition Type | Holley Dual Sync Distributor |
| Injector Connector | Jetronic / Minitimer (Bosch) |
| Product Type | HP EFI Kit |
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
4.7 ★★★★★
Based on 2374 reviews
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Product Reviews
★★★★★ 5
hobbyist only
Purchased to replace a 15 year old Epson. I still have three weeks to decide to return this so I will edit this review if I decide to do that.
PROS: After a few test prints, I love the quality of color, the accuracy of reproduction to what I see on my monitor, and the number of choices for print size and quality.
I found, as others complained, that with cheap gloss paper there was puddling of ink. When I switched to my best papers, especially my favorite highest quality matte finish, the results were astounding and I'd do matte for everything.
As for ink usage, I made the choice to go with a cartridge printer instead of the newer high-volume inks because I wanted the archival quality. Test the output for your needs, because I found the "draft" setting produced better on gloss paper.
CONS: Like so many electronics now, you only get instructions if you download and print them.
Second, when the printed photo feeds out, it has been curled and as it feeds into the receiving drawer, wants to drag the wet ink against the body of the machine. You have to be there to watch and push it down with a finger. Cheaper gloss paper in 4x6 size curled up in a little wet roll 1/2" diameter and is not usable AT ALL.
The miniature screen on which to select papers is ridiculous. I wish the computer interface let you make the choices on your computer, but it does not.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 6, 2020
★★★★★ 1
Defective printer and poor wifi performance
I cannot recommend that anyone buy this printer. At this price, I expected a consistently working and decent quality printer. For initial wireless setup with a Mac, we had to spend 45 minutes on the phone with Epson technical support. That got it working. It worked for a couple of weeks and then the printer would frequently lose its wifi connection even though our internet is high quality cable and very consistent. We'd have to turn this printer off and on repeatedly to re-establish the wifi connection. Then after 6 weeks it stopped working totally. After another 45 minute call with Epson, they said it had a hardware failure and we had to return it to Epson and would receive a refurbished unit. This is less than 2 months after buying a new high priced printer that they are suggesting we accept a refurbished unit. Finally Epson said they'd send a new one. We got the new one and did our customary call to tech support to set it up for wireless with a Mac. It turns out they forgot to send the factory ink cartridges in this replacement printer that are required to do an initial setup. We have the Epson cartridges that are spec'ed for this printer, but they have to be the ones that COME INSIDE the printer for the printer to begin its initial setup. So after another 45 minute call, Epson now says they have to send us new ink cartridges for the printer to even print a single piece of paper - even though we have Epson ink cartridges purchased just for this computer. So after weeks of no printer for our business, we now have to wait for another shipment from Epson. Then we will have the next 45 minute call to set it up.. This painful and costly experience has had way too many headaches - all caused by Epson defects and mistakes. We will not be buying Epson again.
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Reviewed in the United States on July 7, 2018
★★★★★ 5
A must have high quality Photo Printer for cheap!
If you’re searching for a high quality printer without breaking the bank , this is the printer for you.
I had spent a good amount of time researching various printers and the picture quality they offered . I really spent my time looking this up . I found that the Picture quality on this printer is incredible .
If you look at other models that can print 13x19 they cost way more. Now the ink capacity I’m not entirely sure about but I do know the ink can be expensive but it’s a trade off for getting an affordable printer without breaking super high quality pictures .
Setup was very straight forward and it makes it essentially easy for anyone to connect to their network to print wired or wireless. You have the ability to print from your phone which is really amazing as well .
All around this printer is great and if you’re hesitant you should just pull the trigger because you get quality with this model and affordability .
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Reviewed in the United States on November 6, 2025
★★★★★ 4
Ink is a problem
Printer is great. It prints very nicely.. had no problem setting up.. it all works fine. What I didn't like is the ink is kind of expensive and doesn't seem to last long. Once one color is out .. you can't use at all. Says "print in black" but it only allows that a few pages then it's done even tho there is black ink left. Epson customer service kind of sucks also.
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Reviewed in the United States on October 10, 2025
★★★★★ 5
Correction: Excellent value, quality and ease of use for color & grey scale; Wi-Fi firmware updates
Straightforward to install on my home WiFi network. The controls and screen are easy to navigate. Firmware updates can be done via WiFi—so much better than downloading an installer to a computer. Surprised that the maximum borderless print size is A3+. I don’t care, because I don’t mind a thin border on 13x19” paper, and intend to print 12x18” or smaller anyway for framing.
Good results on real-world test prints with default color and tonal settings in Apple Photos. Astonishingly, perfect color and tonal range in my full-spectrum, full-dynamic range test print of a storefront on 13x19” Matte paper. A garden scene had true hues—borderless on 4x6” glossy paper—but was a bit dark. You wouldn’t notice if you only saw the print. Full tonal range B&W image on glossy paper lost some highlight detail and mid-tone pop compared to what I got from a commercial print shop using Luster paper, but I’m not seeing a color cast reported by others, which is very good news.
I bought Epson again after a long hiatus because 1) I have a big stock of paper from pre-covid days, 2) ink cost is not a problem for my limited photo printing needs, and 3) the recent price drop offered a very low up-front cost. This one is smaller and very much quieter than its predecessor. It offers Air Print connectivity, but I prefer WiFi, even from mobile devices.
Pretty happy so far. Already useful and B&W may improve with experimentation.
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Reviewed in the United States on August 31, 2024
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