Terminator X gives GM LS1/LS6 engines complete standalone engine control, replacing a junkyard ECU and cumbersome tuning interface with real-time fuel learn and Holley EFI's proven tuning technology at a budget-friendly price. This kit uses a USB/CAN tuning cable in place of the handheld and requires the free Terminator X software for initial setup.
Key Features:
- Designed for GM LS1/LS6 engines with 24x crank reluctor and EV1 injectors
- Real-time fuel map learn removes the guesswork from tuning the base fuel table
- High-impedance injector drivers safely power most stock LS and Holley EFI injectors
- Bosch LSU 4.9 wideband oxygen sensor included for accurate AFR feedback
- On-board 1-bar MAP sensor, ideal for N/A or nitrous combos (GM 12592525 sensor plus 558-416 adapter recommended for 2+ bar boosted applications)
- Vacuum hose adapters included (1/8, 1/4, and 3/16 in.)
- 4 programmable inputs for extra sensors, nitrous triggers, or a trans brake
- Boost control strategies: vs. time, vs. gear, vs. RPM, vs. speed, plus boost safeties
- Single-channel wet or dry progressive nitrous control with rich/lean safeties
- Advanced tables: 4x 1D, 1x 1D per gear, 4x 2D, 1x 2D per gear for custom tuning needs
- On-board diagnostic LEDs for ECU power, engine run, wideband status, TPS/crank/cam signal
- Includes USB/CAN tuning cable for real-time configuration and tuning
- Compact ECU mounts virtually anywhere (LEDs must face up)
- Plug-and-play compatible with Holley EFI gauges, shift lights, and dash accessories (P/N 553-106, 553-111, 553-112)
- Free EFI tuning software for full laptop control
Specifications:
- Engine: GM LS1/LS2/LS6
- Crank Reluctor: 24x
- Injector Connector: Jetronic/Minitimer (EV1)
- MAP Sensor: 1-bar, integrated
- Drive-By-Wire: No | Transmission Control: None
- Handheld Included: No, USB/CAN tuning cable included instead
- Includes: 24x LS Engine Main Harness, EV1 Injector Harness, Terminator X ECU, ECU Main Power Harness, Bosch LSU 4.9 Wideband O2 Sensor, I/O Harness, vacuum adapters
- Part Number: 550-903T
Terminator X ECUs are designed to be mounted with the LEDs facing up.
FAQ
What engines is the 550-903T Terminator X system designed for?
It's built for GM LS1/LS6 engines with a 24x crank reluctor and EV1 (Jetronic/Minitimer) injectors.
Does this kit include a handheld for tuning?
No, this kit includes a USB/CAN tuning cable instead of the 3.5 in. handheld, and requires the free Terminator X software for setup.
Can this system run boosted applications above 1 bar?
For boosted combinations requiring 2+ bar, Holley recommends the GM 12592525 MAP sensor with the 558-416 adapter harness.
Can I add nitrous control with this ECU?
Yes, it supports single-channel wet or dry progressive nitrous control with rich/lean safeties.
What's included with the 550-903T kit?
It includes the 24x LS engine main harness, EV1 injector harness, Terminator X ECU, ECU power harness, Bosch LSU 4.9 wideband oxygen sensor, I/O harness, USB/CAN tuning cable, and vacuum adapters.
