MJLJ V3 vehicle installation guide

EDIS installation

EDIS and coil-pack installation

Since the EDIS module can operate the engine by itself in a "limp-home" mode, with the advance fixed at 10 degrees BTDC, it's recommended you install the EDIS module and coil packs first, and then verify your engine runs before wiring in the MJLJ.

Wire up the EDIS module and coil pack(s) using the following diagram, matching your engine type (EDIS 4 = 4 cylinder, EDIS 6 = 6 cylinder, EDIS 8 = 8 cylinder). Engines with 'even-fire' configurations are supported, which represents the vast majority of 4,6, and 8 cylinder engines in production.

Wiring notes and guidelines

• Use shielded cable for the VR Sensor. Be sure to ground the shield as well. A 2 conductor cable with a foil shield works well.
• Note the VR sensor is polarized- you will not get spark from the EDIS module if it is wired backwards. If you don't see spark, try reversing the connection on the VR sensor.
• Minimize supply voltage variances and especially ground loop problems:
  • It's strongly recommended you power the EDIS module and MJLJ from the same electrical circuit. Typically this will be +12V switched (Key to "on" position)
  • Important! - Ground both the EDIS and MJLJ at the same point on the chassis.

Installing the MJLJ

MJLJ wiring notes and guidelines

• The MJLJ should be installed inside the passenger compartment. It's not designed to handle the temperature,vibration and moisture extremes of the engine bay.
• Use shielded cable for the PIP/SAW signal between the MJLJ and EDIS module. Be sure to ground the shield as well. A 2-conductor cable with a foil shield works well.
• Use 16 gauge wire for the MJLJ ground connection. 18-20 gauge wiring is fine for power and the other connections.
• For MAP based setups ignore the TPS connections.

Interfacing to Tachometers

Using the TACH OUT on the MJLJ

Many tachometers can accept the signal emitted from the TACH OUT on the MJLJ module. This TACH OUT signal provides a 12V pulse for every ignition event. You may use this to provide the signal to compatible tachometers.

Tachometers that require a HV kickback pulse

Some OEM-style tachometers detect the RPM signal by sensing the high voltage flyback pulse from the ignition coil. In distributor based setups, there is only one ignition coil to detect this pulse from. With a wasted spark system, this 'signal' is spread across multiple coils. As a result, you will need a way to combine these pulses across multiple coil packs to drive your tachometer.

The following circuit allows the flyback pulse to be detected across individual coil packs while still isolating the coils from each other.

OEM tach adapter circuit
If the above circuit does not work, try omitting the Zener diode.

User defined outputs

The User defined outputs provided by the MJLJ can be set to trigger on either RPM or Load thresholds. The configuration of these outputs is provided by the PC configuration software, covered in a later section.

Each output can supply up to 500mA, which is enough to drive LEDs, small incandescent lamps, relays, and small solenoid valves. If you are unsure on the amount of current drawn by the accessory, you can power it manually and measure it's current using a Volt-Ohm-Amp meter.

Accessories that have a higher current demand can be controlled by relays, with the MJLJ output driving the relay.

Should you exceed the current capacity of one or more of the user defined outputs and damage the ULN2003 chip, replace the chip with a new unit- it is socketed for this specific reason.

Enabling Option Switch (For MJLJ firmware > 3.1.0)

For MJLJ firmware version 3.1.0 and later, the Option input is used to enable on-the-fly switching between Ignition Configurations, controllable via a dash mounted switch.

To enable this feature you must have controller firmware V3.1.0 or later installed, and the feature must be enabled in the controller (covered later). Wire the switch based on how your MJLJ is optioned; use the following diagram as a guide: