microRusEFI 4 Cylinder ECU (Legacy)

US$475.00

microRusEFI is our older standalone ECU (2019) for engines up to 4 cylinders. It runs current rusEFI firmware, but for a new build one of these is a better fit:

  • uaEFI, from $275: up to 6 cylinders, with wideband controller, knock input, baro sensor and dual electronic throttle on the board.

  • nano, from $225: 1-2 cylinder engines.

  • uaEFI 121, from $375: one 121-pin automotive connector, optional metal case.

All boards side by side: ECU comparison.

Buy microRusEFI if you already run one, need a spare, or your harness is built for it.

On the board

  • 4 injector outputs (high-impedance), 4 ignition outputs (5 V logic)

  • 2 high-current low-side outputs (idle valve, VVT, solenoids), 4 low-current (relays, lights), main relay output

  • 2 logic-level outputs, 5 V or 12 V by resistor change

  • Inputs: crank VR or Hall (pick in options), 1 Hall, 10 analog + 4 temperature

  • CAN and USB on the plug

  • One 48-pin connector

Check before you order

  • 4 cylinders only. Two injectors per output will burn the board, 6 cylinders is not validated.

Options: crank input VR or Hall, with connector kit or with pigtail.

Docs and support. Interactive pinout. Manual and firmware: wiki.rusefi.com/microRusEFI-Manual. Help comes from the community only: forum, Discord, Facebook group. One-on-one help is sold separately as Technical Support.

Shipping. From New Jersey, USA. In-stock orders usually ship within 5 business days.

microRusEFI is our older standalone ECU (2019) for engines up to 4 cylinders. It runs current rusEFI firmware, but for a new build one of these is a better fit:

  • uaEFI, from $275: up to 6 cylinders, with wideband controller, knock input, baro sensor and dual electronic throttle on the board.

  • nano, from $225: 1-2 cylinder engines.

  • uaEFI 121, from $375: one 121-pin automotive connector, optional metal case.

All boards side by side: ECU comparison.

Buy microRusEFI if you already run one, need a spare, or your harness is built for it.

On the board

  • 4 injector outputs (high-impedance), 4 ignition outputs (5 V logic)

  • 2 high-current low-side outputs (idle valve, VVT, solenoids), 4 low-current (relays, lights), main relay output

  • 2 logic-level outputs, 5 V or 12 V by resistor change

  • Inputs: crank VR or Hall (pick in options), 1 Hall, 10 analog + 4 temperature

  • CAN and USB on the plug

  • One 48-pin connector

Check before you order

  • 4 cylinders only. Two injectors per output will burn the board, 6 cylinders is not validated.

Options: crank input VR or Hall, with connector kit or with pigtail.

Docs and support. Interactive pinout. Manual and firmware: wiki.rusefi.com/microRusEFI-Manual. Help comes from the community only: forum, Discord, Facebook group. One-on-one help is sold separately as Technical Support.

Shipping. From New Jersey, USA. In-stock orders usually ship within 5 business days.

option:

Community Support only. rusEFI does not have technical support stuff.

If you buy this, you should be prepared to follow rusEFI development carefully and be interested in tinkering.


OFF ROAD USE NOTICE: items sold through rusEFI LLC including tuning products may be designed for off-road/race use only, and are not applicable for vehicles in states that require pollution controlled vehicles. California (CARB) & other states prohibit the sale or use of some aftermarket parts, including those that tamper with, modify or defeat emissions systems in any 1966 and newer vehicles. rusEFI LLC prohibits the use of these products on emission controlled vehicles. These parts are sold for OFF ROAD, RACE-ONLY, ground-vehicle use only in a controlled environment.

rusEFI LLC does not implicitly or explicitly confirm the legality of using any products it sells on public roads. Customers are solely responsible for ensuring all products purchased are used in a legal manner.