SKU: 5946477168

Holley Terminator X Engine Management Systems 550-909

Sale price$719.98 Regular price$799.98
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Ships within 48 hours · Estimated delivery Jul 9 - Jul 14

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Description

Holley Terminator X Engine Management Systems 550-909TERMINATOR X MPFI, LS1 W EV6 Take control of your LS engine with Terminator X! Don't settle for a junkyard ECU with a cumbersome tuning interface when you can have complete control of your engine, self learning fuel strategies and the proven, race winning technology of Holley EFI at a budget friendly price! Terminator X features real time fuel learn, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs.

TERMINATOR X MPFI, LS1 W/ EV6 

Take control of your LS engine with Terminator X! Don't settle for a junkyard ECU with a cumbersome tuning interface when you can have complete control of your engine, self-learning fuel strategies and the proven, race-winning technology of Holley EFI at a budget-friendly price! Terminator X features real-time fuel learn, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs. The inputs and outputs are ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. Terminator X comes fully loaded with base maps for common LS engine combinations to get you out of the garage and on the road/track fast. The 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions. Also included is Holley EFI's industry-leading, easy to use software suite that allows full laptop access for advanced users. Whether you are building a budget beater or a boosted race car, Terminator X has the features and technology you need at a price that won't break the bank!

Features:

  • For GM LS1/LS6 engines with 24x crank reluctor - with EV6 Injectors.
  • Real-Time fuel map learn, takes the guess work out of tuning your base fuel table.
  • High Impedance Injector Drivers will safely power most Stock LS injectors, and Holley EFI Injectors. Injector support chart provided in the instructions (Will not control Low Impedance Injectors)
  • All of the new Terminator X systems utilize the Bosch LSU 4.9 wideband to relay AFR information to the ECU for accurate reading and precise tuning control.
  • On-Board 1bar MAP sensor, is perfect for N/A or Nitrous engine combos. If your combination requires a 2+Bar, we recommend GM 12592525, and our adapter part number 558-416.
  • MAP Sensor vacuum hose adapters (1/8th – ¼ and 3/16ths)
  • 4 Inputs – 12v, Ground, 5v, and Frequency, for things such as additional pressure sensors, or activation triggers for nitrous activation, or a trans brake
  • Boost Control – Boost vs Time, Boost vs Gear, Boost vs RPM, Boost vs Speed, Boost Safeties
  • Nitrous Control – Single Channel of Wet or Dry, Progressive or Non-Progressive, Rich/Lean Safeties, and target Closed Loop AFR
  • Advanced Tables – 4x 1D Tables, 1x 1D per Gear Table, 4x 2D Tables, 1x 2D per Gear Table, can be used for any custom tables you can dream up, such as Flex Fuel Sensor Offset Table, or a custom fuel or oil pressure safety!
  • On-Board Diagnostic LEDS for: ECU Power – Engine Run – Wideband Status – TPS Calibration – Crank Signal –Cam Signal. Allow you to identify any Critical engine issues at a glance
  • The included 3.5" Touchscreen Handheld contains a calibration wizard, that allows you to quickly build a base tune for any LS engine. Additionally the handheld provides internal data-logging and a fully customizable gauge display.
  • The compact ECU size allows you to mount it virtually anywhere. Remember, diagnostic LEDS must face up!
  • Plug and play compatible with more Holley EFI accessories such as; analog style gauges, shift lights, various modules, and coming soon, 12.3" digital dash support!
  • Free EFI Tuning Software for complete control of your Terminator X power plant
  • Includes: 24x LS Engine Main Harness - EV6 Injector Harness - Terminator X ECU - ECU Main Power Harness - Bosch LSU 4.9 Wideband Oxygen Sensor - Input/Output Harness - and assorted vacuum adapters.

Specs

Brand Holley EFI
Crank Reluctor 24x
Emission Code 3
Ignition Type GM LS 24x
Injector Connector USCAR (EV6)
Product Type Terminator X LS MPFI
Terminator LS Options Fuel, Spark
Part Number 550-909
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. 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
SKU: 5946477168

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Austin Morris
San Leandro, US
★★★★★ 5
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Blake
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Good watch for a budget, color is good. The pins holding the link together tend to wear out and fall out. Other than that it worked good.
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Reviewed in the United States on January 14, 2026
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JWells
West Palm Beach, US
★★★★★ 5
Nice Watch
Color: 5885 Siver Stainless Steel/hon Dial, Color: 5885 Siver Stainless Steel/hon Dial
Nice watch for the money. I've only had it a week but seems to be keeping good time. From 20 feet away might be mistaken for "Trump Time". The watch design is actually a copy of the Rolex Submariner for a whole lot less money. Several watch companies have copied the Submariner. I removed one link at a time when resizing the band. By the time I got to the final link, the supplied tool wasn't working. I had to remove the final link with a hacksaw and pliers.
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Reviewed in the United States on December 22, 2025
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Danny
Belleville, US
★★★★★ 1
DIDN'T LAST LONG
Color: 5885 Gold Stainless Steel/Gold Dial
Bought this in June 2025, and only wore it a few times. Recently noticed the time was "off" and the seconds-hand wasn't moving. I thought it sat too long and needed to be wound up. So, I wound...and wound...and wound. Never met any resistance in the crown during clock-wise winding...just continued to spin freely, and the seconds-hand never moved. It's a pretty-looking time piece, but don't waste your money if you expect it to keep time. 👎
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Reviewed in the United States on March 25, 2026
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Geraden Christensen
Bozeman, US
★★★★★ 3
Great watch, terrible resizing tool.
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Watch is great, feel heavy, looks beautiful in person. It shines pretty heavily. My main issue is with the resizing tool it comes with. It broke when I tried to use it. Be prepared to buy your own like I did. I can’t say how the fit is yet because I can’t wear it yet. It is not easy to set up.
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