Tutorial : Megasquirting an European (MAP) AE86 (4age)

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This tutorial will hopefully help you to convert an ae86 to run on a MegaSquirt (MSnS)

Parts needed:
1. MS1 v2.2 (v3.0 can also be used with some deviation from this tutorial)
2. An igniter from a MAF 4age (these igniters have 2 wiring connectors instead of 1)
3. Stock wiring harness
4. You will also need soldering iron, wire, etc…..
5. A stimulator is advised but not required

If you never assembled a megasquirt I don’t recommend buying one already assembled.
Assembling a megasquirt gives you a notion about the different electronic components, and improves your ability with the soldering iron.

Assemble your megasquirt and make sure all is working (play around with the stim and the laptop)

With this procedure you are going to use the MAF igniter to condition the VR signal from the distributor in to the MS

This procedure has been done in 2 Portuguese AE86’s that have done several km over the last 3 years without a single glitch.

This procedure is an adaptation from the JamesL setup. (Thank you)
http://www.diyautotune.com/tech_articles...rt_122.htm


V2.2 board changes

Once you have the board assembled and tested with a Stim Kit, you have to modify the board to recognize the NE signal and generate a proper IGT pulse. To do this, you need to modify the MS input and output circuits. I used MS board V2.2 – these instructions are only good for that version of the board. I’m no electronic expert and used modifications recommended by James Murray, the developer of the MegaSquirt n Spark-Extra code.


To properly condition the input signal, you need to:
-- Remove D9
-- Install a 1k resistor between the right side (non-band) end of D5 and the right hole (banded) end of D9. (This provides a 12v pull-up on the input) (Note: I soldered the resistor to the leg of D5, about an 1/8th inch above the surface of the board.)


On the output side, assuming you’re using the FIDLE circuit for ignition control:
- Solder a 1k resistor between the left (non band) end of D9 and the small hole above D9. [Resistor can be 1k to 10k - it is a pull-up to +5V on the output to ignition.]

That’s it – the board should be ready to communicate with the Igniters.
Wiring

Wiring wise
there are 2 major things to be done:

1st
Patch cable …..

There are 3 ways to do this.
1. You can cut your wiring harness and solder the DB37 there
2. You can go to the scrap yard and find an old ECU with the same connector as yours and just use the connector.
3. You can remove the connector from the original ecu

The standard ECU has a code for each pin printed on the PCB ( ex : +B , VCC, NE, etc)

I will leave you with a list of them and where they should connect:


+B1 ;-; Switched battery source (hot both cranking and running). Goes to pin 28 on MS
+B ;-; Switched battery source (you can use it to feed your new wideband lambda sensor)
FC ;-; Fuel Pump relay. Goes to pin 37 on MS

E2 ;-; Main grounding circuits to engine block. – to MS pins on top row, 7-11,
THW ;-; coolant temp sensor – to MS pin 21
VTA ;-; variable throttle position sensor – to MS pin 22
VCC ;-; stable TPS signal for reference – to MS pin 26
THA ;-; air temperature sensor – to MS pin 20
IGF ;-; old ignition confirmation signal, now RPM input from MAF igniter – to MS pin 24
OX ;-; narrowband lamda – to MS pin 23 (if you have a wideband input the wideband signal to pin 23)
STH ;-; TVIS activation – to MS pin 31, if using X14 output. (Refer to JamesL setup for TVIS usage)

E1 ;-; Main grounding circuits to engine block. – to MS pins on top row, 7-11
IGT ;-; Ignition timing signal (from MS to MAP igniter) to MS pin 30 (using FIDLE output for ignition)
#20 ;-; circuit to injectors – to MS pins 33
#10 ;-; circuit to injectors – to MS pin 32
E01 ;-; Main grounding circuits to engine block. – to MS pins on top row, 7-11
E02 ;-; Main grounding circuits to engine block. – to MS pins on top row, 7-11


It might make your life easier if you check this 2 URL’s

http://club4ag.com/faq_and_tech_pages/EC...04A-GE.htm

http://www.megamanual.com/v22manual/extwir.gif



2nd:
Igniters…..

Your MAF igniter should have 8 wires. From left to right they should be :
Black; yellow; brown; red; white; blue; green; black

Your MAP igniter (the one installed on the car) should have 6 wires. From left to right:
White; red; brown; brown; yellow; black

If you have these wiring colors on both your igniters continue, if not you might have to find out the pinout of your igniters.

First thing to do is to cut the White wire that comes from your MAP ignitor into the green connector (cut it at about halt it’s size) this wire is the ignition confirmation signal witch is not used in the megasquirt, we are going to use it to feed the MS with a conditioned distributor signal.

Next connect the green wire from the MAF igniter to the wire you just cut ( this way connecting the MAF igniter green wire into the White wire on the connector plug )

Sorting out the +12v the brown wire that comes from the connector plug must connect to the + side of the coil, both brown wires on the MAP igniter and the brown wire on the MAF igniter.

Finally the red and white wire from the MAF igniter (the ones with a connecting plug of their own) should connect to distributor VR sensor (on the 4 tooth wheel, not the 24 one) to do this you need to cut the distributor wires and find a plug to connect them to the MAF igniter (the distributor connects to the wiring harness originally.)
Try not removing the distributor (assuming you had the timing set properly with the standard ECU you don’t want to change that, it bring another variable into the equation), removing the cover should be enough for you to see what wires come from what sensor, if later one you find out that the RPM signal is not so good you can remove the VR sensor from the 24 tooth wheel.

Resuming, the distributor 4 tooth VR signal sends a wave into the MAF igniter, this wave is then converted in to a square wave (digital) and delivered to the megasquirt. This gives megasquirt the RPM signal and engine position. The megasquirt then delivers the order to fire to the MAP igniter witch fires the coil.

It would be possible to use only the MAF igniter instead of using both, but they tend not to last very long.

Final notes

Bare in mind that the original injectors are low impedance, if your going to upgrade to bigger injectors I recommend getting high impedance ones.
If you do want to use low impedance injectors I recommend buying an injector driver board to assist the megasquirt with them. http://www.jbperf.com/p&h_board/index.html#Buy

This tutorial only covers some hardware. For TVIS activation and software configuration please refer to the JamesL setup.

http://www.diyautotune.com/tech_articles...rt_122.htm

As James says in is own tutorial:

This article is designed to provide general information on the setup I used. You should do your OWN RESEARCH before attempting this project. I AM NOT an expert on MegaSquirt or Toyota ignition systems. I’m just a guy that likes to play with cars……

Gonçalo Manuel [email protected] 23/08/2008 Portugal