How to MegaSquirt Your Nissan 280ZX Turbo

Application: 

• 1982-1983 280ZX Turbo, or conversions using the 82-83 turbo distributor 
• 1984-1989 300ZX, both turbo and non turbo.

Level of control:  Full Standalone EMS– Fuel and Ignition Control

There is already a great write-up by ‘mobythevan’ at Hybridz.org on how to MegaSquirt the 280zx turbo using the MegaSquirt-I PCB2.2 ECU, combined with an HEI-4 module, but what about the more recently released PCB3 ECU?  Certainly you could use it the exact same way and follow the same document combining the MS with the HEI-4 module and end up with the same result, but what about that snazzy new IGBT High Current Ignition Coil Driver that’s built into the PCBv3.0 ECU?  I was recently contacted by a customer that wanted to try and go this route, and I told him I’d make the necessary modifications and document the process for others to follow…  so here we go!

Note – want to trigger a distributorless ignition or sequential injection from the stock distributor? We now offer a bolt in trigger disc that gives you that option. It needs slightly different mods and settings; see this article for how to set it up.

ECU Modifications

You can use an MS3 with the MS2 mods shown here, although to take full advantage of the MS3’s capabilities, it is better to use our L28ET trigger disc upgrade to allow sequential injection.

Using the MS-II PCBv3 or V3.57 ECU

• Build the ECU up to trigger from the Hall/Optical Input (all of my MS230-C units are by default configured this way)
  • For a V3.0, connect TachSelect to OptoIn, TSEL to OptoOut
  • For a V3.57 board, put JP1 in the 2-3 position and J1 in the 1-2 position
• The only change is to enable the IGBT High Current Ignition Coil Driver Circuit to directly drive the coil.
  • Remove the jumper from JS10 to IGN or the center hole of Q16 (if exists)
    Jumper IGBTIN to JS10
  • Jumper IGBTOUT to IGN (V3.0 only)
  • If you do not have a BIP373 transistor in the Q16 slot, install it.
    

Note – if using MS2/Extra, you can also build the board as shown in the MS1 example. You will need to change the spark output pin from JS10 to D14.

Wiring

The input side of things will be the same as mobythevan’s setup– it’s the output side of things that will change.  Here’s a diagram of how to wire it all up if you’re laying out your own wiring harness. This diagram assumes you are splicing the connector from the OEM Nissan wiring – color designations are for the Nissan wiring harness, not the MegaSquirt wiring.

And alternately, here’s a diagram for how to wire up the relay board if you choose to use it:

Thanks to Chris Lupkin for permission to use this drawing

Distributor Wire Colors in the OEM Wiring Harness

Colors of the wires on the distributor side of the 4 pin round connector, versus on the harness side.  You can connect in from either side.

On our current harness for standard MegaSquirts, the MS trigger wire is the white wire in the shielded tach input, and the black wire in the shielded tach input is a ground. You can power the distributor from the same source where the MegaSquirt gets power.

TunerStudio Configuration for MS2/Extra (based on 3.3.3 or later code)

• Spark mode: Basic Trigger
• Trigger angle / offset: Start at 90 degrees. Adjust with a timing light as needed.
• Ignition input capture: Falling edge
• Spark output: Going High
• Number of coils: Single coil
• Spark A output pin: JS10
• Dwell type: Standard dwell

What to Order

MS2 Build:

• MegaSquirt‑II V3.0 kit or V3.57 assembled unit
• 8′ main harness or 24″ pigtail
• JimStim + power supply
• Wideband O2 system