Megasquirt FAQ

My recent MS install has stirred up some questions and interest and since im fresh from being completely ems retarted and just went though the "about to buy,build,install, and tune my first EMS" I feel I can really help explain this to the next guys.

 

IF your the diy type person here, read it yourself, otherwise I'll pull out the important stuff for you..

 

----WHAT IS A MEGA SQUIRT? no its not something dirty or an adult product. The MegaSquirt line of Engine Management Systems are Do It Yourself (DIY) systems capable of full standalone engine management at a fraction of the cost of the what the 'big dogs' charge. They were designed with education and performance in mind, so that the do it yourselfer could learn the in's and out's of engine management and tuning, while learning a good bit about electronics in the process if you choose to build the unit yourself. What you end up with is an incredibly performing EMS that you built yourself for ultimate bragging rights when you leave your buddies behind as a speck in your rearview mirror. And you did this for a quarter to a tenth of the cost of a 'big name' retail standalone ECU.

Building and installing a MegaSquirt EMS will require that you do some homework. Some of the questions and answers below will help to guide you on where to start this and how to go about it. You will learn a lot in the process and if you so choose you will come out of it with the knowledge to properly tune your car for the current configuration you have now, and for any future power combo you can dream up and implement. There is no limit to what you can do or to how much power you can make with this engine management system.

 

----What Do you need to do to have one in your car?

First, you gotta figure out what you want from your EMS(engine management system).

Do you just want a stock like ecu with no add ons? just something you can tweak and tune?, for power or mpg? something for a full blown car with more money in the motor then the car?

 

These are all very important questions. my route was stock fuction to begin with and the room to expand later after i got tuning down and then install the built motor with the turbo and all that jazz were i would add built in boost control.

 

So im going to run you though my exspearience. At first i didnt know were to begin so i read, i read, read some more, went and stared at my car, read some more.

 

Some key things to learn now and remember are these

 

there are whats called MS1, MS2, and MS2 (im useing ms2)

What makes a MS 1 2 or 3 is the processo?r

I have a MS2 processor, the processor is something you dont and cant assemble, MS1 is a 40 pin IC, simple, the MS2 is more a chip with 40 pins that plug into the main board the same way as MS1, MS3 is where things step up a bit to an area i have not even read into. and frankly is more for engines with more cylinders, like 8 plus.

 

now i metioned boards? what are boards! well its like the mother board of the EMS, its what the main 37 pin connector plugs into and same with the serial port, i have a 3.0 board because it provides the most function while still haveing room to expand with hardware mods

What is the difference between the MegaSquirt PCB 2.2 / PCB 3.0 / PCB 3.57?

They are all three able to use the MegaSquirt-I CPU as well as the MegaSquirt-II and MegaSquirt-III daughterboards, but they are based on different versions of the circuit board and as such there are different features . You can click on any of the headings below to view an example of the product with pictures.

PCBv2.2

 

The v2.2 board dates back several years, it's the least expensive of the currently available options, and the least developed. It's a great low budget solution that has served many people well (and continues to).

 

 

 

PCBv3.0

 

The v3.0 board has a lot of improvements made to it to reduce electrical noise and increase robustness (damage resistant), as well as make the board easier to expand. All of the improvements with the V3.0 board are listed here.

 

The main high level differences are that the uprated flyback circuitry is included so you can run low or high impedance injectors, there are several improvements to make the board more robust and harder to damage in the event of a mis-wire or overload event. A prototyping area was adding to the PCB, and several changes were made to prepare the board for the MegaSquirt-II and MegaSquirt-III Daughterboards.

 

 

 

PCBv3.57

 

The v3.57 board's major claim to fame is it's 'surface mount (SMT)' design. Otherwise it is almost identical to the v3.0 board and the above information on the v3.0 board fully applies. The only other major differences are:

 

A) the addition of a PWM capable idle control transistor allowing control of a PWM idle valve or a standard on/off type FIDLE valve without need for modification. This was a common modification applied to the v3.0 board and is no longer needed on the v3.57.

 

B) the addition of a DB15 connector next to the DB9. By default this doesn't do anything, but is there to allow for extra I/O for modifications. It takes the place of the externally viewable LEDs, which are now internally surface mounted on the PCB.

 

C) Several signal pads have been added making common modifications easier.

 

D) The prototype area was sacrificed (removed) to make all of the above possible.

 

 

 

In general, if you're looking for the cheapest option possible, the PCBv2.2 makes sense. Chances are you'll mate an MS1 processor with it in this case, such as with the MegaSquirt-I kits and assembled units. Otherwise, if the small difference in price is worth it to you to go with a tougher and more featured board that was built with expansion in mind, the v3.0 or v3.57 boards make more sense. they offer MegaSquirt I's, II's, and III's using these two boards. Some prefer the thru hole v3.0, and some prefer the v3.57. See the above to decide your preference between the two.

my own kit build.... MS2 with 3.0 board/ just noting out everything for tomorrow morning

wiring, oh god the wiring, i would really like FSMs of all years of these car so post them up or email them to joeswagon(at)gmail.com

sensors and crank trigger setups.

 

In the past MS did not support our ignition set up. But that's all changed now. I would go with a MS2 setup which I highly recommend cause thats what I did:D

 

MS1 may be cheaper but to my knowledge it don't support our setup in full. Ms2 will let you use all stock sensors.

 

Sensors you will use if you go my route:

Stock crank vr sensor

Stock coolant

Stock tps 0-5 volts

You can use the stock idle air controllor but I didn't care to look into how to wire it up plus if you don't use the out puts for it you can use them to run a EBC and I find the car starts fine without it and the proper coldstart enrichment. You will also get rid of that high idle during warm up. Which, yes I know, helps warm the car up.

The stock front o2 can be used but your gonna Wanna go wideband to help tuning. I used the innovate lc1. 180 bucks from amazon.

You DONT use the stock mad. You rid of that and use the inboard mapnsensor which is good to about 20 psi. You just run a vac line to your ems location. Careful not to pinch the line or you will be scracthing your head for awhile.

 

That's really all there is for sensors.

The stock 2nd temp gauge runs right to your dash gauge.

The stock oil pressure sensor just tips of your light on the dash.

 

Now here is where things get tricky. Kinda.

The stock cam and crank sensor setup we use is called the subaru 6/7. The crank reads 6 blips off the crank gear and the cam reads 7 pieces of metal in the upper drivers side cam gear. This is also why if that cam gear is off the car runs super bad.

Now you can use this 6/7 as its supported in the MS2 extra firmware. Not the normal firmware.BUT the same firmware also support the subaru 36-2-2-2 set up.

Btw if you have not figured it out yet this is how the ecu(stock or not) "sees" where and how fast the engine is spinning.

 

Now you could stay with the 6/7 bit that means more wires. More pins in use. More room for error. And most import more wires that can get noise. Noise is shit that interrupts the crank/cam signal. I have read storys about how much junk the 6/7 setup can gather and be a you know to hold a soild rpm ssignal to redline. Now if I have not convinced you 6/7 sucks yet well good luck. I was convinced and didn't go that route.

 

Now that's talk about me me. And what I did. I mentioned 36-2-2-2 and that's what I did. This setup is a new crank gear all together and when read by the crank sensor provides enough info without a cam signal to let the ecu know what stroke and speed the engine is at. You cannfind this 36-2-2-2 wheel on newer subarus, though n/a cars still use the 6/7. Idk why.

 

Next is the ignition system

Megatune was one of the first and still serves many well and john could expand on mega tune as thats what he used but i use tuner studio, you can down load is free here(looking for hyperlink later). if you spend the extra 50 you some extra cool dashboards like in the videos posted below and you get autotune VE anylese. its a neat function that will build your fuel map based on your A/F table.

 

Yes, you can make a table just like a timing or fuel table but for A/F ratio and tunerstudio will try to adjust your fuel map to get the right A/F per rpm and load.

 

i recomend not looking at this entire thread for awhile as its just now hitting me how much work i really need to include and how much proof reading needs to be done as my typing and spelling is nothing to cheer for.

i recomend not looking at this entire thread for awhile as its just now hitting me how much work i really need to include and how much proof reading needs to be done as my typing and spelling is nothing to cheer for.

 

If you moving forward though this right now you can message me or contact diyautotune, they are more then happy to help people, to a point, because nearly every setup can be different.

Awesome, now that I know about this crap I am going to be temped to do it...

 

Try to use lists, it makes it easier for the n00bs and creates less questions lol

 

Look forward to the rest of the information

Subscribed....great thread for people looking at ms.....

 

Just wanted to give you kudo's

 

Dave

Subscribed in case I go this route with my swap.

howdy, i have megasquirt 3 in my 05 legacy been running with it for over 2 years now daily driver.

Thanks guys. I always wonder why more people in the suby world don't use Ms. You have these people paying 1500 plus and saying they built there car and not bought it.

 

I really wonder if those 1500 dollar ems blab blab hydro and aem have anything Ms cant be built to do or have software written

 

Sent from my SCH-I800 using Tapatalk 2

In for more info as well as this is on my list of things to do in the next month.

 

What do you do about baseline maps? Can you download the factory baseline maps and tweak them? Or how do you go about it?

you can maybe find base line maps from other useres on the ms forums.

i could always email you my base line NA map that would also start a car with boost, just dont hit boost till you tune it right.

 

BUT...the map that came in the msextra firmware started my car right up.. well map wise.. i had to adjust some ingition and crank pickup settings. all i gotta do is fire the laptop up and post some videos of my settings. that is of course if you have the same ingition which i sure you do but everyone here has the subaru 6/7 crank/cam signal pick up, i ditched that in favor of losing the cam sensor all together, keeping one more spot open on the 37 pin connector, and to make things simple. BUT i did have to swap to the subaru 36-2-2-2 crank trigger that comes on the newer subarus, pics later.

 

been busy cleaning the house, only have till feb to get rid of all my garbage and stuff and i work everyday and trying to work on my car at the same time. you never relise how much shit you can collect in 10 years untill you have to move/remove it all haha.

my last week before basic training and i never got back to completing this.

 

nor has anyone ask me to.

fyi for people wishing to do engine swapsin newer subarus, megasquirt has a expantion board called tinyiox. it is capable of making any crank and cam pseudo signals to make the stock ecm happy. i have this installed on my car for about 2 weeks now.

Say what? ^ Been having issues with cam and crank signals on a megasquirt system.

its makes fake signal if you have a swapped engine.

 

what crank signal issue are you having?

you must be running 2 or 3 to have a cam sync and sequential injection?

if your smart enough to swap an engine why the hell cant you swap over the original trigger pickups from the crank or cam?

uh ? well if your going from 4 cyl to 6 cyl the stock computer can't realy deal with that.

 

the 6 cyl has a different built in crank trigger and cam trigger scheme.

 

if one has a 05+ subaru that uses can network and you want your dash board to work and cruise control to work you need to send the stock subaru ecm a mock signal.

Megasquirt!

yea check out megasquirt.com

While this new MS3 Pro is completely unnecessary over the existing MS3X, it is an amazing solution for people who need their car running tomorrow with minimal effort and fuss http://www.diyautotune.com/ms3-pro.html

Great when compared to the price of competitors. Not for me, but still was so excited I had to post The thing can run nearly any engine, even the more complicated offerings from the line-up of BMW or Mercedes (though why would you )

While to each its own, Megasquirts can become super finicky and unreliable. I much rather save the time and headache and just buy an AEM. IMO.

^ how so? i have been running it since 2001 only time i had an issue was a bad solder wire that i did in the main connector. and that still didn't stop me from driving home