SKU: 39296231040

Holley Terminator X Engine Management Systems 550-905

Sale price$719.98 Regular price$799.98
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Ships within 48 hours · Estimated delivery Jul 13 - Jul 18

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Description

Holley Terminator X Engine Management Systems 550-905TERMINATOR X MPFI, LS2 LS3 & LATE TRUCK 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

TERMINATOR X MPFI, LS2/LS3 & LATE TRUCK

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:

  • Designed for GM LS Engines with 58x Crank, 4x Cam - and 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.
  • 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
  • 4 Outputs – Ground, PWM - , for accessories such as; fans, boost control, nitrous control, IAC Kit, and More
  • 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
  • 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
  • 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!adjustable through included 3.5” f
  • 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: 58x/4x 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 58x
Emission Code 3
Ignition Type GM LS 58x
Injector Connector USCAR (EV6)
Product Type Terminator X LS MPFI
Terminator LS Options Fuel, Spark
Part Number 550-905
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: 39296231040

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Matthew Anderson
Louisville, US
★★★★★ 5
No problems after a year and a half
Color: Dogwood & Calming, Size: Medium
Have been regularly buying these for my corgi for about a year and a half. The 2 pack lasts about a month or 2 each time. Pieces break off in small enough pieces that they safely pass through his digestive system. He gnaws each one down to about 1/4 the original size before we take it away and give him a new one. He continues to have regular bowel movements and has a healthy appetite so I can’t imagine any problems arising after so long. I have tried other alternatives and every other similar chew breaks off in larger pieces and didn’t feel comfortable letting him chew/eat them. I noticed there are a few 1 star reviews saying their dogs got sick off these but after a year and a half I have had 0 issues with this product. I guess it depends on the dog and how big of pieces they are swallowing. My dog ingests pieces about the size of a grain of rice so just pay attention and you should be fine.
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Reviewed in the United States on February 18, 2026
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terlynn4
Draper, US
★★★★★ 5
Long lasting and safer alternative to sticks
Color: Dogwood & Calming, Size: Medium
These are great, very durable, and have lasted a very long time. Much safer for my dogs than the random sticks they find in the yard. They do get shorter with chewing eventually, but they don't break off in little chunks like I've seen with some nylon chews, and they don't splinter like wood. Medium size works well for both my 16 lb Cavalier and my 60 lb Pyrenees/Golden mix. They're both moderate-to-aggressive chewers, though size obviously affects how much damage they can do. I wish you could buy the hemp chew separately because that one is very much a favorite in my house, so after 2 years and 2 purchases, I have barely any left of the remaining hemp chew, but still 2 of the dogwood chews that neither dog is as interested in anymore. I'd love to buy a couple more of just the hemp one.
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Reviewed in the United States on April 30, 2026
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Shannon Brace
Phoenix, US
★★★★★ 5
Your dog will thank you.
Color: Dogwood & Fresh Breath, Size: Large
My dogs loves to chew on these. They make a small mess but not as bad as other chews. They are food for keeping teeth clean.
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Reviewed in the United States on May 31, 2026
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Anna
Port Orchard, US
★★★★★ 5
Nice chew toy
Color: Dogwood Mushroom, Size: Medium, Color: Dogwood Mushroom, Size: Medium
Super durable and puppy loves it. It was a bit hard for her at first but now at 5 months it’s one of her favorite things to gnaw on! It is heavy for the size but seems to be great quality and has given many hours of chew time with minimal wear.
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Reviewed in the United States on March 12, 2026
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Jennifer
Whiting, US
★★★★★ 4
Long lasting
Color: Dogwood & Calming, Size: Medium
My dogs love these bones.
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Reviewed in the United States on March 25, 2026

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