Megasquirt Project

[CanadianYank]

After much debate, I have decided to use a Megasquirt for my 818s ECU, mainly to simplify my harness and my build… I will document the project here for others benefit.

The motor is a 2000 JDM EJ205 removed from a WRX Wagon with a TD04 turbo, no AVCS, no TGV’s, no CAT’s (Its nice living in Alberta!) The engine will be equipped with the following sensors:

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After-market Cable throttle body w/TPS sensor
Stock PWM Idle valve
Stock 550cc yellow top side feed injectors
Crank belt pulley 36-2-2-2 tooth trigger
Stock crank sensor
Stock Wasted Spark coil pack with integrated igniter (Diamond, PN FHO161)
GM IAT sesor
Stock Coolant temp sensor
AEM wideband O2 sensor and Gauge UEGO Controller
Microsquirt II V3.57 with DIYAutoTune’s DB37 Harness

The plan is to remove the stock 6 tooth crank trigger and replace with a newer style 36-2-2-2. This way I should not need to use the cam sensor for timing of the MS2. The 6 tooth vs the 36-2-2-2 gears are shown here.

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I have created a preliminary drawing of the system here for reference…

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The MS2 will be set-up for Batch Fire mode Injection and Wasted Spark Ignition. Here are pictures of the Megasquirt II V3.57 with harness.

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This is what I have researched and understand so far and I'm in no way and expert on the Megasquirt, as this will be a learning experience for me. Please if anyone here has experience or recommendations to share it will be welcomed and appreciated.

Updates to follow..

Frank

[Arrowhead]

Pretty cool your going with a Megasquirt. Did notice a couple of things though. You can setup the auxiliary contacts to turn your cooling fan on and off based on coolant temp. Also you show the TPS, CLT and IAT sensors grounded. These should have discrete ground wires and be wired back to the Megasquirt internal ground. Any poor ground from the engine block to the MS with a one wire sensor will give you erroneous signals and the potential for interference (although you may already know that but just showed it that was for simplicity).

You may also want to think about getting the MS relay panel. It has termination points for the main switched 12v, 12v hot and ground and all the sensors. Plus it has a fused ECU relay and fuel pump relay. Pretty sure the third relay can be used for the fan. (been quite a while since I built mine) But it's normally used for the Fast Idle relay which it looks like your planning on using. you could still run your fan, you'll just have to have a separate relay for it

http://www.diyautotune.com/catalog/megasquirt-relay-board-assembled-unit-p-32.html

[STiPWRD]

That electrical diagram looks fairly straight forward. I had a few questions as I'm not familiar with Megasquirt but have heard of them many years ago.

1. Does the auto tune feature mean that you can program an AFR curve and the Megasquirt will auto correct to achieve that curve?
2. What does something like this cost?
3. Does Alberta require an OBD2 system to pass registration?
4. Do they make a USB compatible version? Looks like the one you have is RS232

[CHOTIS BILL]

“The plan is to remove the stock 6 tooth crank trigger and replace with a newer style 36-2-2-2. This way I should not need to use the cam sensor for timing of the MS2. The 6 tooth vs the 36-2-2-2 gears are shown here.”

Would you explain further how this works? I am not familiar with how that would work.

Thanks,

Bill Lomenick

[CanadianYank]

Pretty cool your going with a Megasquirt. Did notice a couple of things though. You can setup the auxiliary contacts to turn your cooling fan on and off based on coolant temp. Also you show the TPS, CLT and IAT sensors grounded. These should have discrete ground wires and be wired back to the Megasquirt internal ground. Any poor ground from the engine block to the MS with a one wire sensor will give you erroneous signals and the potential for interference (although you may already know that but just showed it that was for simplicity).

You may also want to think about getting the MS relay panel. It has termination points for the main switched 12v, 12v hot and ground and all the sensors. Plus it has a fused ECU relay and fuel pump relay. Pretty sure the third relay can be used for the fan. (been quite a while since I built mine) But it's normally used for the Fast Idle relay which it looks like your planning on using. you could still run your fan, you'll just have to have a separate relay for it

http://www.diyautotune.com/catalog/megasquirt-relay-board-assembled-unit-p-32.html

Arrowhead thank you for that, I will make a change to the drawing to reflect the discrete signal return to the MS2. Hadn't thought of the fan control yet Ill look into adding that as well.

Frank

[CanadianYank]

STiPWRD, I copied your txt here and answered each...

That electrical diagram looks fairly straight forward. I had a few questions as I'm not familiar with Megasquirt but have heard of them many years ago.

1. Does the auto tune feature mean that you can program an AFR curve and the Megasquirt will auto correct to achieve that curve?

Yes, video here for explanation.
http://www.youtube.com/watch?v=p5_2Ct2l62M

2. What does something like this cost?

I bought the MS2 PCB V3.57 already assembled. They are going for around 400.00 or so online. I bought mine from DIYAutoTune. You can buy the kits that you assemble yourself much cheaper. The latest standard is the MS3, I had bought this unit for another project but decided to use it for the 818...

3. Does Alberta require an OBD2 system to pass registration?

Nope, Moved to Canada two years ago from NY and my 2006 Corvette C6 has Kooks long tube headers no cats 3" Xpipe and modded Z06 mufflers and it passed the RIV import inspection. They also do not have yearly inspections...

4. Do they make a USB compatible version? Looks like the one you have is RS232.

I use a usb to serial adapter. I have a simulator that plugs into the MS2 DB37 connection so I can play with the laptop and adjust settings with just the ECU. The adapter works well, Ill post a pic of it later tonight when I get home...

Frank

[CanadianYank]

“The plan is to remove the stock 6 tooth crank trigger and replace with a newer style 36-2-2-2. This way I should not need to use the cam sensor for timing of the MS2. The 6 tooth vs the 36-2-2-2 gears are shown here.”

Would you explain further how this works? I am not familiar with how that would work.

Thanks,

Bill Lomenick

Hey Bill,

From my research reading through the manual here. http://www.msextra.com/doc/pdf/MS2V357_Hardware-3.3.pdf

Its a new Hardware Manual published 8-29-2014 using the MS2/Extra code 3.3.x


Subaru 4cyl engines
Typically, the cam sensor is not used and "wasted spark" or "wasted COP" should be used.
The recommended wiring uses internal high current drivers to drive the standard high-current coilpack. It
requires two high current ignition outputs - see section 5.3.0.2
Typical settings:
Spark mode = 36-2-2-2
Trigger Angle/Offset = 0 (tweak if required)
Ignition input capture = Falling Edge (typically)
Spark Output = Going High
Number of coils = Wasted Spark

The coilpack I'm using has 4 wire plug. 12VDC, Ground, and two Triggers from the ECU. I have the same coilpack on my 2.5L donor so I measured the output of the ECU to coilpack signal and it does not go over 5VDC so I can use TTL logic... Im using two spare outputs to drive the coilpack 5VDC logic level outputs from the ECU. The V3.57 board has the MOD as part of the PCB and just needs jumpers soldered from PAD1 to IAC1a and PAD3 to IAC1b to get the triggers out the DB37 harness. At least that's the plan...

Frank

[CHOTIS BILL]

Thanks for the info. It would then appear that you will be using batch injector firing and not sequential.

Bill Lomenick

[CanadianYank]

Thanks for the info. It would then appear that you will be using batch injector firing and not sequential.

Bill Lomenick

Yes as the 818 will be a street car that I AutoX and I wasn't worried to much about emissions, I chose batch over sequential for simplicity and performance. For those that don't understand the difference here is a good explanation. http://www.enginebasics.com/EFI%20Tuning/Batch%20vs%20Sequential.html

Frank

[STiPWRD]

The auto tune feature off of a wide band voltage is a very cool feature indeed and something I've only seen on much more expensive stand alone engine management systems. I will definitely keep this system in mind if I ever build a race car. Unfortunately I need OBD2 to pass emissions :( and I'd have to get over the giggle factor of buying a system called Megasquirt

[CanadianYank]

The auto tune feature off of a wide band voltage is a very cool feature indeed and something I've only seen on much more expensive stand alone engine management systems. I will definitely keep this system in mind if I ever build a race car. Unfortunately I need OBD2 to pass emissions :( and I'd have to get over the giggle factor of buying a system called Megasquirt

Cant you can just make another engine harness for the MS and keep the original ECU in place for Inspection?

Frank

[CanadianYank]

Made some changes from the input from Arrowhead, Thank you.
Going to use IAC1/JS0 for the relay output.

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Frank

[CanadianYank]

Ok, I think I'm done with the preliminary drawing, I'll start working on my engine harness this weekend...

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Frank

[CHOTIS BILL]

Do you have any idea why Subaru uses a 36-2-2-2 tooth trigger? I am sure they have a very good reason for doing it and I am curious what that might be.

Thanks,

Bill Lomenick

[CanadianYank]

Do you have any idea why Subaru uses a 36-2-2-2 tooth trigger? I am sure they have a very good reason for doing it and I am curious what that might be.

Thanks,

Bill Lomenick


Not for sure the reason why but did some reading as to what it does.


36-2-2-2 set-up has 36 crank teeth division with three sets of 2 missing. Each tooth 10 degrees graduation.
missing 2 teeth BTDC Cyl 1 (long gap from 60 to 30 BTDC cyl1)
and 2 teeth twice before BTDC Cyl 3. (long gap from 60 to 30 and 30 to 0 BTDC cyl3)

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From what I understand reading the MSExtra code I should only need the 36-2-2-2 wheel for timing running batch fire injection and I can set my dwell via the laptop.

I'm trying to figure out how I can start the JDM EJ on a test stand of some sorts so I can play with this. I'm driving the donor this winter so no parts available from the wagon. Maybe just need to find a transmission housing...

Frank

[Wayne Presley]

I worked with DIY on developing the code for the Subaru and have a tune file if you want it.

[CanadianYank]

I worked with DIY on developing the code for the Subaru and have a tune file if you want it.

Wayne, yes please that would be great.

Frank

[biknman]

I know this is old but do you have the visio or cad file or the stencil symbols you used to create this diagram that you would be willing to share? I want to produce the same sort of wiring diagram but with COPs.
Thanks
Dave