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Ignitions and Electrical› Computers, Chips, Modules and Programmers

Diy autotune

Engine Control Unit (ECU) with MS3X Expansion

$799.99 $699.99 Save $100.00

SKU: MS3X357-C

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Special Order
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$100 Minimum Order
30 Days Return
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Overview

The DIYAutoTune MS3X357-C is a MegaSquirt 3 ECU with MS3X expansion. It features 8 sequential fuel injector outputs and 8 logic level 5-volt ignition outputs, along with 6 medium current outputs. The system includes 3 analog inputs, 4 switch inputs, and 1 cam sensor input.
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The Diy autotune MS3X357-C is a powerful and flexible engine management solution designed for serious racers and custom builds. It offers advanced features that surpass earlier MS1 and MS2 systems, providing precise control over critical engine functions. This ECU boasts capabilities such as sequential fuel and spark, boost control, 2-step launch, progressive nitrous, and onboard traction control. It features 8 sequential fuel injector outputs, each capable of driving high impedance injectors, and 8 logic-level ignition outputs that support smart coils like IGN1A and LSx coils. Additionally, it includes 6 medium current outputs ideal for fan control or boost solenoids, 3 analog sensor inputs for external sensors like MAP or O2, 4 switch inputs for functions like launch control, and 1 cam sync input compatible with various sensor types. The MS3X also offers advanced tuning resolution with 16x16 VE and ignition tables and high accuracy for fuel and ignition steps. Data logging is supported via a built-in USB port and an SD card socket (SD card sold separately). Idle and mixture control, including closed-loop AFR control, are also included. Note: This ECU requires external ignition drivers or smart coils. An SD card and wiring harness are sold separately and must be acquired to complete the installation.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandDiy autotune
Part NumberMS3X357-C
CategoryIgnitions and Electrical
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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