SKU: 39296231040

Holley Terminator X Engine Management Systems 550-905

Sale price$719.98 Regular price$799.98
Save 10%

Pay in installments of $200.00 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 26 - Jul 31

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

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

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.4 ★★★★★
Based on 25 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
K
Verified Purchase
Kam
Bozeman, US
★★★★★ 5
Great prom suit
Size: X-Small, Color: Royal Blue-3pieces
The quality is awesome. Just needed a few alterations and my done is set for the prom
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 10, 2026
S
Verified Purchase
Serina Anthony
Phoenix, US
★★★★★ 5
Fun alternative to traditional tuxedo
Size: Large, Color: Black-2 Pieces, Size: Large, Color: Black-2 Pieces
Fairly good quality. Hubby wore this as fun alternative to his regular tux in a cruise elegant night. Looked sharp and we even got family pictures in it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 13, 2025
O
Verified Purchase
Octavia Ward
Carnegie, US
★★★★★ 5
Great for price ⭐
Size: Small, Color: Blue-2 Pieces, Size: Small, Color: Blue-2 Pieces
Bought this for my son's junior prom and it looked so good on him. I had to get a few alterations done because it was a bit too big for him but all in all great quality for the price.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 8, 2025
J
Verified Purchase
Jennifer
Cuba, US
★★★★★ 5
Quality suit at an amazing price!
Color: Black, Size: Large, Color: Black, Size: Large
This suit was perfect for my son’s senior prom. Quality material and fit him perfectly! This was ideal when you don’t want to rent a tuxedo, knowing he will use it again and again. He looked so very handsome.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 24, 2026
A
Verified Purchase
AW
Port Orchard, US
★★★★★ 5
Great suit!
Color: Black, Size: Small
Great suit! Suit is well made for the price. Very comfortable, nice material and could be worn for any occasion no matter the time of year. We ordered according to the size chart and fit great! Would be easy to do a little tailoring if needed tho. Came in quick and is exactly what we needed. Will be ordering other colors for the future!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 29, 2026

recommand products