This is an account of my recent efforts to get a Megasquirt full standalone ECU powering my KA-T. I will try my very best to make sure it is complete and accurate, but you should not blindly follow it as a comprehensive step-by-step guide.

I bought a fully assembled Megasquirt 1 version 3.0 from Matt at DIYautotune.com. I highly recommend buying from him. He has experience with squirting 240s, and was ALWAYS a great help to me as I had various troubles along the way. Some slight modifications need to be made to his fully assembled boards. You can pay an extra $20 for him to do it. See this article here, for more info on that: http://www.diyautotune.com/tec...x.htm

I suggest you read that all the way through, as it will get you well on your way. THE INFORMATION I AM PROVIDING HERE IS MEANT AS A SUPPLEMENT TO THE INFORMATION PROVIDED IN THAT ARTICLE.

Now, on to the wiring. I suggest you get yourself a copy of the FSM and look at the foldout section.

For wiring up the idle control valve:

For idle control I am using the stock a/c FICD valve, and it seems to work just fine. You need to locate the wire going from it to the ECU. It is green with a blue stripe and it goes to pin 45. You need to connect that to a relay, and then connect the relay to ground. Ground it far, far away from everything else. Then give the + coil side of the relay 12v and connect the -ve coil side to the Fidle pin on the megasquirt. Now go to your engine harness. The plug you want is one of the ones on the front of the engine, specifically the one that is ziptied to the valvecover breather line. You can verify that you have the right one by checking where the wires go. If they go under the manifold, to the valves on the back, you have the right one. Splice the brown wire in with the blue/green wire (only the end leading to the valve). This will provide the valve with constant power when the key is on.

Guess what, the stock ecu controls the tach!

That's right folks. If you want to use your stock tach you need to wire up a little circuit. See this picture taken from the MS manual: http://www.msextra.com/manuals...o.GIF

Where it has the 1-10k resistor, I used a 1200 ohm one and it worked for me. I also used a different transistor (one I had laying around) so it might be slightly different for others.

Ignition:

For some reason the stock coil and transistor don't seem to want to work with MS. I ended up using a MSD blaster SS coil. Note that since the VB921 in MS has current limiting capabilities, you won't need a ballast resistor. MSD states that the optimal dwell time for this coil is 3.50 ms.

Using the stock temperature sensor:

You can easily use the stock sensor, but you need to calibrate MS to read it with Easytherm. Search it up and follow their instructions. Or, if you don't/can't remove it and test it, use these numbers (what I got with mine):

-4 F 5190 ohm
86 F 480 ohm
210 F 207 ohm

The SCV system:

If you haven't removed those stupid butterflies from the intake manifold, you need to ground the solenoid that controls them. Grey wire, pin 25.

I think that about covers it. Do all of the stuff in that article from DIYautotune.com, then do what I have said, and you should be well on your way.

I will add more information as I go along/think of it.

Now comes the tuning. Have fun.

Modified by ZiG at 7:08 PM 9/14/2007

Horsepower (hp) = Torque (ft-lbs) x RPM / 5252

I'll probably be ordering my MS within the next 3 weeks. I'm going to go with the MS-2 pcb 3.0.

have you gotten your idle problems sorted out yet?
And when you get a chance could you link your msq? i've been doing a mixture of calculating settings mathematically and randomly guessing. so if i could actually look at a semi working tune that would be awesome

it's mostly the ignition settings i'm not really sure about.

Today there was a meet for the local 240sx club, and I managed to make it down there. Everyone was pretty impressed. What really amused me though, was that there is another guy with a 'squirted 240 (though he paid a shop to do it all) and he couldn't believe that I had managed to get mine to start the first time, every time. haha.

Yeah about the tune.. I don't currently have anywhere to host it. I put it here for now: http://files-upload.com/files/...7.msq

If you know somewhere I can upload it for free/for ever, please let me know. Otherwise I guess people can just give me their email and ask me.

About that tune: I got the base VE and spark tables from another guy on KA-T.org. They seemed very reasonable so I just loaded them up and went. Idle is pretty much a perfect 14.5:1 AFR, and it gets pretty rich under boost (hey, better that than too lean). The spark map is pretty tame, but again, it's always good to start on the conservative side. It's perfectly driveable for me as it is. I've just been driving around with autotune turned on, and this has been the result of a few hours worth of fine tuning. My setup is as follows:

SR t25
SR 370CC injectors cleaned & flowtested (didn't need to be balanced)
knocksense MS knock light (Highly recommended)
innovate LC1 wideband with in-dash gauge

And I think that's all that's relevant.

Ok everyone: go start squirting.

There's a book I've been reading recently called "How to Tune and Modify Engine Management Systems" by Jeff Hartman. I got it on ebay for $3 shipped.
The book runs through everything about how the ECU actually works, the sensors involved, and how it controls all this to make the engine run.

I learned alot from it and i'm sure it will help with the tuning of the megasquirt.

I'll email you the file.

SO i renamed it to a .txt which is kinda nice because you can open it and see whats in the msq. Just remember to rename it to open in Megatune.

There's Zig's current tune.
http://www.geocities.com/kraze...g.txt
to use this in megatune rename the extension to .msq

Here's the ignition map from zig
http://www.geocities.com/kraze...p.txt
rename the extension on the ignition table to .vex

Hope this helps anyone looking at the megasquirt system. I'm planning on doing MS2.. and will probably order everything next week. So expect updates as i attempt to build and tune everything.

Keep me updated!

WD

On My buddies 93 we just used the ignition wire as our main power for everything(coil/fuel inj/cas/ms itself ).
What and how did you relay off components?

We started with megafire coil but after destroying vb921 realized its suppose to be used with msd or cdi box only. Went back to oem coil 4 now.

The VB921 is a high current transistor that should be able to drive most coils.. You DID make sure you were triggering off the -ve terminal, and in Megatune you have 'Spark output inverted' set to YES, right?

this is from the post:
""
BLASTER SS COIL SPECIFICATIONS
Primary Resistance: .355 ohms
Peak Current: 300mA
Secondary Resistance: 6.2K ohms
Spark Duration: 180uS
Maximum Voltage: 48,000 volts
Primary Inductance:
6mH

reply:
Your coil is designed for use with an MSD box .
Most coils have 3 to 4 times as much resistance as your present coil .

It will put out less spark power than your stock coil unless
it is driven by a CDI type ignition box like this :
Multi-Spark CDI Ignition

Your VB921 will drive the white wire on this box or an MSD box ,
(wiring is identical in both units) .

"""
Vb is somewhat being re manufactured so its hard to find in Canada. And Usa shipping is 8x the chip.

But i looked around and this coil my buddy has I so far only seen used with conjunction to megafire ignition moduals. So i am waiting for few more vb's and than going with oem coil 4now. Gotta get this project outta the garage already.

Squirted: megasquirt200709141747.msq

Stock ignition: ZiG_stockignmap.txt

Thanks man!

A little update: I don't like using the AC Fidle solenoid for idle control. It idles either just a little too low (still smooth but I worry about low oil pressure) or it idles at like 1100 RPM. Which I suppose is porbably fine, but I'm going for perfect here.

On that note I have finished modding it for a PWM IAC and I'll hook that up tomorrow or something. It should be noted that if you really want to, you can bypass idle in megasquirt altogether, all you would have to do is wire up the AC Fidle solenoid to be on whenever the key is, and then fine tune it with the idle speed screw. The lazy man's approach. Or perhaps the approach of the ambitious man that decided to squirt in the first place, but got annoyed at the project and decided that as far as idle goes, close enough is good enough. haha.

Now i did get the kit, not the pre-assembled. But hopefully i should have the Megasquirt itself assembled within a week. Then i'll just order the various sensors i need and dig into the wiring harness.

I've been researching all the firmware options, and made my final decision that i'll be running the MS2 extra firmware. which is currently in the 1.02 release.
It has some really cool stuff in development for it like 16x16 tables, boost control(MS1-E has this already), and some other stuff.

I'm planning on doing the same as Zig and reusing as much of the factory harness as possible. But if i get ambitious i may go through it later and completely redo the whole harness.

And good choice with the ms2/extra. When they develop it a little more I'll probably switch to it too.

The only sensor you'll need is the iat. And remember to put it in the cold pipe.

Where did you buy it from?

i got the kit from diyautotune.com also. They seemed really helpful in talking with them.

probably Wednesday everything will arrive in the mail. So hopefully i can find the time to get it built, then i can worry about getting it into my car.

I hope for your sake that your s13 isn't your only transportation. It is for me, and rigind my *** on the bus to school (engineering student) for 2 weeks REALLY sucked. But I guess I had a lot of problems I had to figure out, so hopefully the things I learned will help others to finish it faster.

Good luck and keep us posted.

*shudder* stupid bus.

I was able to get my car running and idling great with a slightly different setup. Also, from everything iv read MS2 is much more difficult to get running than MS1. Even on the MS support forums, i wasnt able to find a single person who ran MS2 successfully on a KA. Just keep that in mind when your choosing between the two.

My setup, like ZiG's was to let MS directly control the coil through the Hall Optical CAS. I was able to get my timing dialed in at a trigger offset value of 72. This will be different for some people, depending on how you have your Dizzy turned, however 72 is enough to get your car running. Some people have said that its 108 or something. While i cant contest this, all i know is that my car ran and held timing dead on at 72.

I however went with the path of least resistance and kept the stock ECU to control idle, tach, AC, ect. I butchered the wiring harness in doing so. However, i cant see any possible way of not doing so if your installing MS.

The main problem i had was tuning startup/cranking pulse widths. I had a great tune after about a week of having my car running and saved over it, and was never able to get it back to that point. I should have just scraped everything i had done and started fresh but i got frustrated of having my DD down for 3 months and went with Enthalpy..

Another issue, the main reason i switched to a stockish ecu, i left my key on one night and somehow fried the VB just by doing so. That was just kinda the straw that broke the camels back.

Oh, and using the MS Dwell calculator, a blaster 2/3 coil has an optimal dwell time of 2. Matt said this was a little low and i could try to crank it up, but with the dwell set at 2 i had no issues. If you want to crank the dwell up higher, open the MS case while its sitting at an idle for a while, and put your finger over the VB unit. If its to hot to touch, your dwell is to high.

I recently picked up a front wrecked 240 and plan on using MS for it(track car? as long as the frames strait!) , so we will see how that goes.

Stimulator is finished, Megasquirt board will have power, serial, and most of the clock circuits finished by this afternoon. So it's going really well. I'm going to wire it in initially just using the factory wiring. Then over the winter, while the s13 is off the road i'll make my own wiring harness then swap it out in the spring.

found a great amount of info on MS2/MS2extra with the KA from a guy called KApower on the forums.
here's his success thread.
http://msruns.com/viewtopic.php?t=22422

the awesome part is the guy has put a great deal of work into documenting his project so he has diagrams and everything for setting up the board.

just as a note to anyone looking at megasquirt or any other tuning, the great guys at Injected Performance have a deal running on widebands so take a look
http://forums.nicoclub.com/zerothread?id=281562

Yeah I saw that guy on the ms success stories.. Not much applied to me though, and he wouldn't answer PMs.

His thread has a bit of decent info on it, but its not all that helpful.

The one thing i found interesting was the fact that he adressed the number of squirts per cycle issue. I had the same issue when i ran two squirts, changed it out to 4 and it fixed the issue much as that guy said.

ZIG how many squirts do you run? Did you have the same issue with it stumbling off idle with two?

I'm going to a dyno with a guy that's tuned many, many megasquirted cars, this coming tuesday. It should be awesome.

Zig you might want to take a look at this.
FSM states these readout for the factory CLT.
68* F 2.1 - 2.9 K ohms
122* F 680 - 1000 ohms
176* F 300 - 330 ohms

I bought myself a new one from one of the sponsors and got 17,500 ohms at 12* F. So.... your sensor appears to be a bit off

on the other hand i'm hoping to have my MS2 finished this week and probably start the wiring redo weekend. So far everything is looking good with the stim and megatune.

In any case, after 1.5 hours of dyno work:

Modified by ZiG at 9:48 PM 10/2/2007

Megasquirt LIVES
Tonight i finished building my MS2. Honestly the DIY kit is worth the savings from getting a prebuilt. It only took me a week to put it together. i'd have to say that the 6-8 hours assembly is just about right, and if you have the time it's definitely worth it.

Passed all stim/megatune testing and everything looks great. I've got 3 more mods to do to the board then it's good to go(tach input pullup, tacho out circuit, and a relay control circuit)

btw this is what i'm planning on doing for timing. I'm going to mess with the dizzy and trigger angle until the values in the bin is the actual measurable timing.

If tomorrow isn't too crazy i think I'm going to put my LC-1 in, and just use the narrow band output for the factory ECU for now. Then hopefully this weekend i can start on the wiring harness modifications.

Modified by krazydriver at 9:29 PM 10/3/2007

Modified by krazydriver at 9:31 PM 10/3/2007

Modified by krazydriver at 10:39 PM 3/30/2008

What the hell is that skin? is that megatune? looks COOL!

I used to use it solely for the skins, but it has alot of other nice features that allow you to run multiple desktops simultaneously, keyboard shortcuts etc.
Take a look at it. it's pretty cool. There's THOUSANDS of skins online and the program allows you to make your own if you want

..Also nice to have in linux.

i was just wondering how you'd wired up the power to the megasquirt. I was planning on taking the switched power from the factory EFI relay, then running that into a fusebox then from there distribute power to everything as seen in this picture.

i was planning on just running the thermo fast idle for now. just so i won't have to interface anything else with the megasquirt.

Did you have to add any relays to get everything to work? or should i be good doing it this way?

On a side note though one of the diagrams in the FSM shows that an air regulator gets power when the fuel pump is on. I'm not positive but it looks to be the IACV air regulator. So maybe i won't need to run power and ground to it?

I modded the ecu relay and the power to the injectors as shown in that diagram, and the MS itself still gets power from the 2 wires that power the stock ECU.

I'm going to take a bunch of pics of how i wired everything, so expect updates with pics tomorrow/wednesday.

Using stock coil or what?

('cause if you are, you'll have to bypass the power transistor if you havent already. And even then, might be iffy.)

alright here's how i wired the megasquirt power and grounds. I ran a completely separate relay as shown below. I'd like to leave as much of the factory wiring as possible, at least until megasquirt proves it can make my car run. At that stage i'll be revising the below drawing because i'll be powering the fast idle thermo switch and (if i don't remove them) the solenoid for the butterflies.
right click and view image to clear it up

Megasquirt and the LC-1 share a ground point. I'll probably leave the rest of the sensors on the factory ground lines, and i'll get up some actual pics of the wiring madness tomorrow.

For sensor wiring just follow the megasquirt external wiring diagram i posted further up.

To remove the constant 12v to the injectors
To cut the constant 12 volts to the injectors just go down right next to the battery and the washer fluid filler. You'll see a grey connector. Unplug it and from the cold side(if your worried you can just unplug the battery) i just removed the connector for the red wire.

I'm going to be using the thermo switch fast idle which only needs 12v and a ground to work. Currently it will be receiving both of these through the factory harness... so it should be fine.

If i can get some cover over my car, or if it doesn't rain tomorrow. I think i'll be able to do all the sensor wiring. Most of which will just be extending the factory ecu sensor wires so that they'll reach to where megasquirt is mounted. if the wiring goes well maybe i'll post up a first startup (or failed startup) vid.

I look forward to seeing the end result!

I'd been testing while i wired so i knew power worked, i'd done the output test for coil and injectors. So i fired up megatune and switched it to realtime.
Calibrated the TPS, and made sure everything looked like a reading i should be getting.

Turn the key.... crank sputter
Try it again.... crank sputter
3rd time Crank VROOM!!!! SHE LIVES!!!!

won't idle so i have to keep blipping the gas to keep it running...
then i realized that the hose to the MAP sensor had popped off the fitting as the map is reading atmospheric. All other sensors look fine, tach readout is great

Turn it off fix the map hose, she fires right back up. Still won't idle(not really sure if the fast idle i wired up is working or not). I screwed with the trigger angle some more, i'd started at 78, moving to 86 allowed me to let the car fall below 1000 RPM before it starts missing, so i just gotta tune the ignition somemore. But my laptop battery died... oh well more fun for tomorrow.

And here follows pics of my wiring job, it still needs to get bundled and ziptied out of the way.
I apologize for the crappy pics but all i had available was my cellphone camera... so they are what they are.

and here's the msq i was using.
http://www.geocities.com/kraze...7.txt
Unfortunately i can only host on geocities at the moment, so i had to rename it to a txt. So you'll need to change the extension to .msq. Because i'm running the MS2/extra code you'll also need to download this version of megatune to open it.
http://msextra.com/ms2extra/fi...r.exe

So for today i'm done, tomorrow i'll definitely have some time to screw with it and hopefully get a decent idle going.

just ziptie the iat sensor somewhere for now. On a turbo car it needs to go in the coldpipe because the air is a different temperature due to the compression and intercooler, but on a n/a car having it ziptied in the engine bay somewhere in the general area of the airbox will be just fine. Actually I had to do that with the iat sensor in my Firebird when I installed a CAI. heh.

As for your trigger angle, have you checked it with a timing light yet? Just set megatune to hold 20* btdc and then adjust the trigger angle until you see 20* with your timing light.

As for your idle.. do you have the iacv hooked up yet? Or are you just trying to use the thermal fidle valve?