DIYAutoTune.com Engine Management Systems & Tools

How to MegaSquirt your 280zx Turbo

Directly driving the coil with the MegaSquirt-I PCB 3.0 and MSnS-E 024s9 or later or the MegaSquirt-II

Updated 5/16/2006 Relay Board Wiring Update, Docs Updated for MS-II use

Application: 1982-1983 280ZX Turbo, or conversions using the 82-83 turbo distributor

(Thoroughly tested on multiple 83's, part number comparison shows the 82 dizzy to be the same)

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!

ECU Modifications

It's choice time, MS-I with MSnS-E firmware, or MS-II. The choice is yours. Most thus far have used the MS-I with MSnS-E on these cars.... why? Because it's been around longer, and people want to go with the 'sure thing'. The MS-II is the road less traveled on these cars, but this is the main reason why. There's no reason why you shouldn't consider it as an option and make the decision based purely on the featureset of the ECUs. The MS-I with MSnS_E is extremely mature, has a ton of features, and is pretty near the end of it's development cycle. The MS-II is much newer, faster hardware, though the development is really just getting kicked off, so while it has some features that MSnS_E doesn't have, the reverse is also true in that MSnS_E has some features that the MS-II doesn't have (though most require mods to enable them). The writer of the MSnS_E firmware is about to get a hold of the MS-II firmware and I expect to see some really cool things happen soon...

Using the MS-I PCBv3 with MSnS-E firmware

This is assuming you are starting with an ECU built up like I build my assembled MS130-C MegaSquirt-I PCB3.0 units. If you are building your unit up from a kit you can implement these changes during assembly.
Flash ECU with MSnS-E version 024s9 or later. (How? Click Here.) (Or Here)
Jumper IGBTOUT to IGN to send to IGBT ignition coil driver signal out of pin 36 on the DB37.
Cut out C12 and C30. (Only needed when triggering from the - terminal of the coil, which you are not)
Remove D1 and jumper it, or just install a jumper wire across it's leads. (Only needed when triggering from the - terminal of the coil, which you are not)
Cut out R57 if fitted (this won't be there on my units though).
Get a 330 ohm 1/4w resistor and cut the leads down to about 1/2" at each end. Maybe a bit less.
Tin each end of the resistor with a bit of solder.
Cut a 5" piece of hookup wire (22ga is fine) and strip just a 1/8" or so. Tin the stripped wire with solder.
Melt the tinned wire tip to one end of the tinned 330 ohm resistor tip and let it cool.

Heatshrink wrap this wire/resistor assembly.

Use this wire/resistor combo to jumper the 'top' (top as in when you facing the silkscreen side of the PCB, with the text so that you can read it normally) lead of R26 to IGBTIN on the opposite side of the PCB.

That's it!

Using the MS-II PCBv3 ECU

Build the ECU up to trigger from the Hall/Optical Input (all of my MS230-C units are by default configured this way).
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 (if exists)
- Jumper IGBTIN to JS10
- Jumper IGBTOUT to IGN
That's it!

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.

Click this image if you need a larger view.

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

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.

Dizzy Side	Harness Side	Purpose
Red	B/W	12v+
White	G/B	MS Trigger (to Pin 24 on DB37, or Relay Board TACH terminal)
Green	G/Y	not used
Black	Black	Ground

MegaTune Configuration for MSnS-E

For now, continue to refer to Mobythevan's documentation for MegaTune configuration of the MSnS-E firmware. You can use the .msq files from PCBv2.2 implementations with this setup-- you'll just need to reconfigure the spark output so that instead of coming from FIDLE it's now coming from D14 (aka LED17). You can do this from inside MegaTune. Select the 'Code Config' Menu, then select the 'Codebase and outputs function' option. Set 'FIDLE function' to 'Idle Control' and set 'LED17 function' to 'Spark Output'.

On the 'Spark' menu choose 'Spark Settings' and set 'Spark Output Inverted' to YES.

If you use someone else's .msq file I do recommend you check the MSnS-E firmware version the .msq file was built on as you cannot always use a file built on one version of MSnS_E with a different version-- it's best to use the .msq files with the same version of the MSnS-E firmware that it was built on.

MegaTune Configuration for MS-II

As this is a 'path less traveled' thus far you probably won't find people with maps to share for your car just yet. You can however dial it in with a bit of patience and some 'how to tune' homework, most of which you can do in the Megamanual at www.megasquirt.info.

Important: On the 'Ignition Settings' menu make sure to set 'Spark Output' to 'Going High (Inverted)' and set 'Coil Charging Scheme' to 'Standard Coil Charge'.

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