Welcome to EFI Extras website.

Parts and Accessories for your Engine Management Installation.

New SPARTAN 3 lite wideband controllers now in Stock!





MicroSquirt V3 ECU with 8' (2.4m) loom

Price: £395 + £15 postage

MicroSquirt V3 MS2 ECU with an 8' (2.4m) loom - £395

See HERE for the Microsquirt Hardware Manual.

MicroSquirt Engine Management Control - with 8′ Harness it is an entry-level, fully assembled ECU capable of running a single cylinder all the way up to 8 cylinders with up to 2 fuel and 4 spark outputs

-Supports speed density, alpha-N (TPS based), or MAF based fuel and spark tables - (MAP sensor not supplied, need

ed for Speed density)

-0.66 microsecond injector pulse width resolution

-Allows blending multiple load types, including specialized mode for independent throttle bodies

-Supports a wide variety of OEM cam and crank position sensors

-Accelerator pump or model based acceleration enrichment

-Closed or open loop idle speed and boost control -On/off nitrous control

-Wankel rotary support: 2 rotor engines with separate leading and trailing spark tables

-Staged injection

-Table switching

-16 x 16 fuel and spark tables

-2 step rev limiter (launch control) with no-lift shifting

-Wideband AFR target table

-Flex fuel sensor input

-Real time barometric correction (external sensor required)

-Sequential shift cut and air shifter control

MicroSquirt Transmission Control Options - MicroSquirt transmission control free firmware allows you to use MicroSquirt with 30″ Harness to control a number of electronic automatic transmissions (gearboxes). It can work standalone or integrate with one of our ECU’s over canbus.

Control applications: GM 4L60E I GM 4L80E I GM 4T40E I GM 5L40E (dev) I A341E I 41TE (dev) I Ford 4R70W I Ford E40D (dev) I Subaru W4A33 & more…


Spartan 3 Lite with Bosch 4.9 LSU Lambda Sensor

Price: £150 + £10 postage

SPARTAN 3 Lite Wideband Controller

Spartan 3 Lite WideBand Lambda Controller and Bosch 4.9 Lambda Sensor - £150

Note: Lambda sensor carries a 3-month warranty

Output Sequencer provides a dual-level precision voltage signal to the Linear Output. This allows you to

easily check that the AFR/Lambda seen by any device connected to the Linear Output is accurate, and if not,

to generate a 2 point calibration to achieve perfect accuracy.

Smart Heatup; Temperature Triggered Heating, Spartan 3 Lite v2 will wait for the Oxygen sensor to be heated

to 350C by engine exhaust gases before heating up the sensor.

For wiring info on the Spartan 3 see HERE.

See HERE. for the Spartan 3 instruction manual.


MS1-2-3 main wiring looms - from £60

These are included with an ExtraEFI ECU, so you do NOT need to order one if you buy an ECU from ExtraEFI.

But if you need a wiring loom for your MegaSquirt, then these are supplied with bare ended wires ready for you to wire to your setups connectors.

The looms are approx 1 meter long with a high quality, screened cable for the trigger signal and multiple 0.5mm ground cables for good noise separation.

Each wire is colour coded and has a label with it's description on it that matches the ExtraEFI diagrams.

As the wiring looms are made to your setup requirements, please contact me with all your details before ordering.


Coolant/Air temperature sensors - from £19

If your engine doesn't have both temperature sensors then it is possible to use a sensor from a scrap yard. But some people like to use the original MegaSquirt sensors as these are the sensors that are used as default in your MegaSquirt ECU - GM

The open style air sensor is ideal for fast changing temperatures from boosted engines. The closed style is ideal for coolant and air temperature sensing in most NA setups.

The thread is 3/8" NPT.

Each sensor is supplied with the connector ready to be crimped / soldered to your loom


MS2X Expansion Board for MS2 ECU's - Sequential 4cy - from £12

Adds 2 Injector drivers, cam input, BlueTooth comms, Inputs / Outputs to an MS2

For more info see HERE.


Price: £25

USB - RS232 adapter - £25

Having tested lots of these adapters I have found this type works fine on various laptops, suitable for all MegaSquirt ECU's.

The driver is available here if you need it.

See here on how to setup an RS232 adapter.


Bosch injector style plug - from £20

This is the standard injector plug used on most vehicles using Bosch style injectors as found on Fords, RV8's, etc.

Each item comes with a rubber boot and 2 crimp terminals for the cables, for best results are to solder the wire to the crimps after crimping.


  • 101.5mm diameter - £30
  • 171.5mm diameter - £30
  • 209.5mm diameter - £35
  • Rover V8/TVR crank pulley with crank sensor bracket and VR sensor - £115

36-1 Trigger wheels -from £30

Wheels are lazer cut 3mm thick, 12.7mm diameter hole in the center and 8 radial aligning slots.

The Rover / TVR wheels are specially made to fit the various versions of pulleys that have been

fitted to the RV8's over the years. To ensure we supply the correct wheel / bracket, we require

a picture of your pulley. So please email me