4G63 / Miata setup.

The MS3+MS3X can easily interface with stock 4G63 CAS, high impedance injectors and standard ignition module.

Crank and cam sensor inputs
These sensors need +12V, ground and supply a 'clean' logic signal for the Megasquirt. The Megasquirt will need setting internally for the 'VR' circuit with a pullup.
See the Tach Input section for V3.0 board or for V3.57 board and following sections.

From left,
Black =Ground
Red = 12V power
Yellow = 'crank' (4 slots) - connects to pin 24 on main connector
White = 'cam' (2 slots) - connects to pin 32 on MS3X connector

Tach external wiring is described here

Ignition outputs are described here

Injector wiring is described here

Settings

On 'Engine and Sequential settings' set Main Fuel outputs to MS3X fuel and enable fully sequential.

On 'Ignition Options and Wheeldecoder' set Spark mode to '4G63', input capture to 'Rising Edge', Spark output to 'Going high (inverted)', coils to 'Wasted spark', spark hardware to 'MS3X spark', Cam input to 'MS3X Cam in'
Trigger offset/angle - start at zero and then confirm by using a timing light.

(Note that this screenshot shows 'coil on plug' not 'wasted spark' as in the text. Select to match your install.

If you have a question, comment, or suggestion for this FAQ please post it on the forum.

No part of this manual may be reproduced or changed without written permission from James Murray, Ken Culver and Philip Ringwood.