How to wire in your megasquirt (at least the one you got from me)

[linuxman51]

So, you've done it.. either you bought one from me (props ;) ) or you rolled your own (props again).
So, your $$ gets you this really cool looking thing you soldered together and hope works..
If you rolled your own and don't have a stim, you can power test it without, i'll divulge that info at the end.

So.... now what? There's been the definitve megasquirt guide, that provides a veritable dirge of good, bad, and indifferent info, and theres been more than one ms&s guide.. well what the hell am I supposed to do now?
Note that this is written with 700 series in mind, you 200 series guys are going to have to interpret and translate on the fly (its not any different, same principles apply)

Calm down.. settle down, grab a beer, and read on...
If you bought one from me with one of my pigtails, then the following is for you (well if you bought one recently. otherwise I should have provided you with a detailed color pinout, refer to that instead of this, i will refer to subsystems from here on out to avoid confusion)

37 -pink
35/34 - light green
33/32 dark green or light brown
30 yellow
28 red
26 grey
25 red
24 light blue
23 purple
22 dark blue
21 orange
20 white
Ground-black or black/dark brown.

You will need: wire cutter, wire stripper, soldering iron, solder, male and female spade connectors (in a pinch just female) DVOM, and a test light, and a timing light for ms&s.

Pin 37 works the fuel pump relay (provides a ground iirc)
35/34 and 33/32 are inj2 and inj1 respectivly, and those are your injector banks
30 is fast idle
28 is switched 12v
26 is a 5v output for the tps
25 is special to me, more on this in a minute (Actually its not, but will be further explained. if you made your own harness, do yourself a favor and connect a wire to this pin)
24 is the tach input/tach signal
23 is the o2 signal
22 is the tps signal wire
21 is coolant temp
and 20 is air intake temp.


here's the new and updated diagram



If you bought one from me, you might wanna pull the silver connector appart and double check to make sure, I might have gotten cute and used light blue and white for air intake and coolant temp.

now for the basics:
The grounds don't have to leave the interior, neither does pin 37 or pin 28
in most cases pin 34/35 won't either, appendix two will cover why i favor one bank of 4 injectors. So you'll need to pull the coolant temp, air temp, tps, o2, and fidle wires through one of the firewall plugs (or on a 200 series, the firewall plug ). There's less **** on the passenger side for 700's, thats the one I personally prefer.


A word of recomendation (post edit here): When hooking up power for the megasquirt, a seperate kill switch is a nice thing to have whilst tuning, as once you make changes it is strongly recomended that you kill power to the unit to fully reset it, We've noticed on every occasion that you dont, "bizzare" behavior is observed, especially whilst tuning the spark map. and it makes for a nice theft prevention kill switch (not that thats been a problem for any of our cars)

Once thats done, forget about the underhood for a little while, its time to dive into your dash and gaze at the wild wonder of volvo wiring hell.. You will want to go ahead and pull the fuse panel out as far as possible to make things easier on yourself, however I will discuss alternatives. Also, you'll want to go ahead and pull out the passenger side kick panel to get at that bastard lh box, and the pedal covers to get at the ezk box (which will have some stuff of interest to the ms&s'ers). Now you can decide to a) splice into the factory ecu switched 12v supply which should be a blue wire, or you can dive into the fuse panel (What i'd recomend barring wierd relay issues) and find out which ones go live when the key is turned. Use your test light for this (you did remember to get one, right?), ground it well, and then probe for a 12v supply that not only comes on with the key, *BUT* also stays on while cranking. yes, some dont (unless you tore the soul out of your car like me and replaced that goddamn mess behind the dash). once located (either on the ecu plug or the fuse panel), run the wire from pin 28 over there, splice it in (or hook it up to that section on the fuse panel, its always a good idea to fuse everything you can in case something grounds out), solder where needed and MAKE SURE YOU TAPE THE SPLICE! if you spade connected to the fuse panel you're probably ok on that one. Now, run the ground over to the ground bank on the passenger side wall, its hiding sorta behind the ecu box. if you pull the ecu out of its cradle you should see it no problem. hook that up, plug in the megasquirt, turn the key on and verify that the leds blink (if you have a laptop, check communication with megatune).
Now, turn the car off, and unhook the battery. I have no recomendations for hooking up the fpr, a standard relay would probably be the best solution as I personally never got the volvo relay working with the megasquirt, YMMV. I used a switch on the dash for the pumps, that way i can fiddle with stuff on the ecu without the pumps running in the background.. I'll leave it as an exercise to the end user to find the wire for the fuel pumps, the test light hooked up to 12v and playing with the relay socket should make fast work of that.

Now on to greater things: wiring up sensors, injectors, and other crap under the hood.
First off, you can't have too many grounds. Second, megasquirt provides a ground signal for the injectors much in the same way LH does, so if you really wanted to be a prick you could once again splice into the ecu connector and do things that way (if you're leaving the stock harness under the hood in case of road side emergencies, this would clearly be the better way). Same goes for the Coolant temp sensor. This info literally changed on a year to year basis (color code wise. Trust me. I've been deep inside 5 700's, and not a damn one of em ever had the same color wire. the socket could be the same, but I dont know that off the top of my head, and I'm not even going to suggest a specific color wire, altho on the lh side i'm fairly sure its a thick grey wire for the injectors, but if thats not it, you've been warned).
Polarity on injectors doesnt matter, so pick one side for power and one for megasquirt, and keep that uniform. You'll want to go ahead and make a 1-4 junction with the inj bank you chose (inj1 is logically the better one, but it really doesnt matter for vanilla ms&s), and go ahead and run 4 wires from the resistor pack (or run the wires for the power side if you're using high imp injectors). the power to the volvo resistor pack goes in on the thick green/red wire, you might want to tie this to the same switched 12v as you did the megasquirt, or better yet, the fuel pump switch/relay. the other side we just discussed so its time to move on to the coolant temp sensor. Again, side doenst matter, make sure you leave yourself enough slack to comfortably tuck the wires away once done, and remember that the ECT is the one between 3&4, not the one up around 1-2 (thats for the gauge). the other side you'll want enough to tie it to a common ground. Did i mention eye connectors would come in handy as well? oops.. Anyway, give yourself enough slack on the ground side to make things look nice as well, and let that wire dangle for a few.
On to the IAT. On my first install, i stuffed this in the intake manfold, however I now recomend that you install this post intercooler, pre throttle body (narrows it down a bit eh), drill a hole thats pretty close, use teflon, and thread the f-er through tight. You do want a tight fit. if you got an oblong hole, jbweld is a viable option. for the wiring, its the same as the coolant temp, one side is ground, one is signal, pick a favorite side and run with it, and give yourself slack on both to work with. dont hook the ground up yet (more on this in a minute) but do see that its long enough to go with the ECT ground.

Now for the tps. I'll ask you to refer to the orriginal ms thread for pics on this, altho really, if you're using the volvo or nissan variable tps, a little common sense, some grinding, and jbweld and you'll be done in 10 minutes. Just make sure you get it going in the right direction. Generally the middle wire is the signal and the edges are the power/ground, when you get it wired up and hooked up to megatune you can tell quickly if its backwards or not, this wont hurt anything, you'll just have to switch the outside two. on the volvo tps, 1 is power and 3 is ground iirc. NOW you get to play with those three grounds. take them, bundle them together in that eye connector you got cause you diligently read this before even attempting to install megasquirt, and ground all three somewhere. I prefer the intake manfold (but then, i've also got a thick ass wire running from there to the chassis ground). again, do it wherever you feel is the best for you. At this time you'll also want to check all other engine grounds. For the o2, if you're not using a wideband, you can hook it up, it didnt do much for me personally, so I didnt bother, signal wire on a volvo is the single wire by itself, you might want to provide power and ground for the other two (again, dont think it matters) if you've got a 3 wire.
So you've done all this cool stuff... you're almost there.
if you're just doing ms, you'll need to run the light blue wire to the (-) side of the coil, and the red wire coming off pin 25 to ground.

for ms&s, heres were life gets really fun. You need to stop everything, get another beer, and get your sober buddy to drive you to radio shack, cuss me along the way, and spend $1.50 on 390 ohm resistors and 10 ohm resistors. You only need two or three, but they come in packs of 5. one (390) goes from pin 24 to pin 28 (pull up resistor), the other goes on the power line to the distributor (10 ohm). the middle on the distro goes to pin 24, and the other side is ground. the connector on the distro should have the polarity labeled. Volvo distros like 12v, the resistor for this goes inline (just stuff it in the middle somewhere), and that switched 12v source from earlier might be the ticket. If you're using the stock harness for the distro, this is where the wiring on the ezk side comes in handy. Pull the rubber back on the connector, determine which three wires you need to tap into at the ecu plug, and then dive under the dash and hook em up. I'm pretty sure the ground and the sheild are one and the same, but i could be incorrect on this, use good judgement, and it should be fairly apparent when you're in there looking at things (there's only three wires). Now....
heres were things get vague alittle, since common knowledge once again changed recently regarding the ignition module for ms &s.. I'm *pretty* sure the 124 and 139 modules are interchangeable in terms of their pinouts, but I can't verify this 100% myself yet. At any rate, with the stock volvo ign. module connector, the thick brown wire is ground, blue is power, red/white is the coil trigger and tach for the dash, and the other two are the ground shield for the trigger and the trigger itself. Mine was in a thickass grey wire. You hook the fidle up to the middle wire, ground the shield (its grounded at the ecu as well, if you're using volvo wiring, again, pull the rubber back and verify things), and another 1k resistor between the fidle and a switched 12v. for the coil power, you can pull power from the module if you'd like, and dont forget to hook the module up to a switched 12v supply.
hook the battery back up, pull the coil wire off the distro, set it where you can watch it, and spin the motor over.. should spark a lot. If it sparks only when you turn the key off, cut the pullup resistor off the filde line and try again. it should spark fairly frequently. Now hook the coil wire back up, hook the laptop up, and play with the trigger angle until the car starts up (it should start on the fuel maps provided, but thats about as far as i'll say they work..).

Tip: megatuneSS provides a "tuning" window where you can set the spark angle output. Set this to 10 degrees with the ecu on, hit enter, and then play with the trigger angle until the car starts. when you've gotten the car to idle, walk around front, hook up the timing light, and check the difference in crank postition vs what megasquirt says, and play with the trigger angle until you get it reading 10 degrees at the crank. then set the fixed angle to 15, verify that it did indeed change 5 degrees, drop the angle to 5, make sure that works as described, burn those values, and its time to tune.

IF: you dont get spark at all:
1) verify that megasquirt is getting an rpm signal, if not see below
2) check for power at the coil
3) check for power at the module
4) double check the wiring for fildle to the module

IF: you dont get an rpm signal in megatune (or a blinking light on the front of the megasquirt box)
1) check to see that the hall sensor has power
2) check to make sure you hooked up the signal wire correctly, and have either the pullup resistor inline for pin 24, or have pin24 grounded if you're relying on volvo ignition. if you're relying on volvo ignition you'll need to manually turn on the ignition box, try again
3) check the ground for the hall sensor
4) do make sure its pluged in firmly, double check the wiring to the board
5) open the box up, see of the D8 diode is installed, if it is, send me a hate PM for forgetting to jump it, solder a jumper wire between the legs and try again (note: if its just for ms, email me and i'll mail out the diode, i didnt install it on most of the more recent boards since very few if anyone requested just megasquirt). So yea, for just MS you might want to go ahead and check and see if that diode is there.
6) you did something wrong somewhere, refer to this diagram to fix it:


IF: you're having issues nailing the trigger angle down OR the engine starts randomly running backwards OR it retards timing instead of advancing it:
1) click the "invert output" option in megatuneSS and try again
2) remove the pullup resistor on the fidle wire and try again, if this fails, see #1
3) try a lower trigger angle value (actually try this first instead of the other two, but once you get it putting 10 at the crank, and saying 10 in megasquirt, then you need to start worrying if its going in the wrong direction)
4) I dunno, hit me up with DETAILS PLEASE a "my car runs backwards" pm will be laughed at and discarded, as there are too many variables for me to even begin to help trouble shoot. Pictures of everything would be nice too. Not underhood shots, i dont want to see that rats nest, i'm talking pictures of how its wired up.

IF: You got the igntion stuff working correctly but the car runs like ****:
1) go tune it. and enjoy doing so. Read the megasquirt tuning guide. then read it again.
2) do not even think about bothering me about a poorly running car until you've spent at least a week tuning, and even then if you're not wideband tuning it i'm not going to be inclined to offer any help. if its a specific problem you can try, but most everything is covered in the tuning guide. No, really, read it twice. maybe even three times.

Notes and addendums:
1) you can test the megasquirt to see if it powers up correctly by hooking up the yellow wire and a black wire from a computer powersupply to pin 28 (hook the yellow wire up here) and the ground (black wire here..durh).
That will at least let you know that the system mostly works. if you have any bizzare readings for gauges, double check those circuits, and yes, its normal for the tps to sit there for a minute and then start counting up slowly.

I had something else i was going to cover here, but it presently leaves me. I'll add more as i remember it.

Ah yes, why I prefer to run off inj1: simply put.. scaleability. Yea, semi sequential injection mgiht be cool, but staged injection is cooler, and ms&s extra supports this. So this is why i prefer to run the primary injectors off of just one inj bank. you could do both if you want, but why waste an output?

[Super1800GTR]

Nice write up!! Does most of the same stuff apply to those of us swapping CIS?? Also do you/anyone have any pics to go along w/ these instructions. I'm trying to visualize what's gonna go where. I understand 90% of the underhood stuff but I've yet to fiddle w/ anything under the dash so that part's a little confusing. IE: "Now you can decide to a) splice into the factory ecu switched 12v supply which should be a blue wire"

Thanks
Rob

[volvoman37]

bible!

[Ceides]

Brilliant writeup. I'm sure this is going to save me a whole lot of time


~Arnar

[n xntrx volvo]

2 is ground on a stock tps

[CoconutColin]

someone pm and me tell me what mega squirt is?

[n xntrx volvo]

Originally Posted by CoconutColin

someone pm and me tell me what mega squirt is?

there's two ways to get megasquirt, one is if its been a mega long time since you've been with a girl, the other is to buy the mega-package of dirty magazines.
-Aaron
ps check here for more info

[kyle242gt]

FYI - the PC power supply might not work, it didn't for me (11.28V or something) and nearly gave me a heart attack!

Also, I'm running 5V to my hall sensor... am I reading that I should change that to 12V? What's a symptom of incorrect voltage?

A great read, Kenny, even for those of us who have done it already... and started forgetting just how they did it

[volvo9]

Great writeup, you've answered the big question I've had, "what's involved in the install".

I'll be reading that a few times and memorising it!

[Benjam83]

This is a great write-up man. I really appreciate it. I just have some questions that might sound kind of ignorant, but it all works out because when it comes to MSnS, lol, I am!!! lol.

Question 1: Ok, you speak of the intake air temp sensor (IAT), is this something that we relocate, something we buy and install between the IC and TB?

Question 2: Is a wideband supposed to be installed in the tailpipe rather than the downpipe? I dunno, i heard this somewhere.

I had another question, but I can't remember it right now.

thanx

[linuxman51]

you have to buy the iat in 99% of the cases, and its better for the wideband to be ~3 feet from the outlet of the turbo, however I ran the lm-1 in the stock o2 location and it seemed to work fine

[The Aspirator]

Originally Posted by kyle242GT

Also, I'm running 5V to my hall sensor... am I reading that I should change that to 12V? What's a symptom of incorrect voltage?

A great read, Kenny, even for those of us who have done it already... and started forgetting just how they did it

I'm also running 5v to the hall sensor, but according to you two I've got some sorta f'ed up wiring schematic...... works great though!

Kenny, are you burning the MSnS firmware onto the controllers for your customers? When I built my MS I just had the Megasquirt firmware on there and couldnt' for the life of me figure out why it wasn't sparking. Well it's because megasquirt didn't know what spark was without the proper firmware.

Also, maybe we need to start a new post or something dedicated to burning the firmware, upgrading to new firmware, new MegaTune programs, and keeping up to date with all the new goodies. Apparently there are TWO new versions of MegaTune since I upgraded to 271 last week.

John

[linuxman51]

yes, I'm flashing to ms&s on the controllers, and you guys with the extra stuff should put heads together and do that. and I wanna see some 1/4 times too...

[The Aspirator]

Originally Posted by linuxman51

yes, I'm flashing to ms&s on the controllers, and you guys with the extra stuff should put heads together and do that. and I wanna see some 1/4 times too...

Okay I'll start a thread eventually. As for 1/4 times, it'll have to wait till next yet. Our track closed weeks ago, so I only got to go once.

John

[linuxman51]

so after the mass mailing, who's gotten their ms installed and running? I know yozzi's is up and driving to a greater or lesser extent, thats 1 out of like... 14.
Lets have some installs documented here folks

[Benjam83]

ok, couple more questions.

You mentioned that we'd have to use a "standard relay" to bypass or whatever the fuel pump relay. What do you mean by standard? Are there certain voltages and currents that it will switch at?

What's an EZK box?

And I'm a little hazy on the whole injector bank part. Maybe I just don't know the lingo or something.

If someone besides Ken wants to field these, be my guest. I'm sure he's getting tired of my damn questions.

Thanks




Mine is getting installed over thanksgiving break. So I'll have a month to tune it for Hangover Fest at the 1/4 strip on Jan 1st

[linuxman51]

a standard relay is just that.. standard automotive relay. They retail for about 4 bucks at any car parts store, and there are a couple under the hood of most bricks that one can steal for such purposes as well. what you're looking for is a 12v relay (sometimes labeled as a foglight relay, the higher the amperage, the heavier duty the relay, anything over 40 should be good for a fuel pump. I'm a sick bastard & bought some 50 amp relays for various things tho)

a bank of injectors is just a set, i.e. the 4 injectors stock on a volvo is one bank of injectors.

ezk is a 700 series ignition ecu

[linuxman51]

another detailed addendum to the above, stemming from recent spark problems with ovlov760

The exact pinout for the bosch 0 227 100 124 module (the one that *ISNT* recomended but will work with a resistor on the coil)

This might actually be elsewhere on the board, but for the sake of general unity, i'll rewrite it more consisely here..

Pin 1 -> Coil (-) ("coil trigger")
Pin 2 -> Ground (chassis)
Pin 3 -> module trigger shield, do nothing with this
pin 4 -> Module + 12v
pin 5 -> Module trigger. this is the wire found inside the thick shielded wire, this is what you connect to the Fidle/ pin 30 of megasquirt. (yeller wire ifin its onea my harnesses)

[n xntrx volvo]

k?

[linuxman51]

cept it doesnt all end up like that and part of that picture is confusing, i'll let you guys figure out which part i'm refering to...

[The Aspirator]

Other than the injector wiring (blue and green wires) it's a very straightforward and easy to follow diagram. At least it lets you visualize all the things that need to be hooked up.

John

[linuxman51]

no, the sensor and injector wiring is probably the easiest part of the diagram, theres other stuff on there that if one looks closely doesnt make much sense, and you dont really notice it until you're wiring it up on the car..

[84superturbo]

i dunno if it's right of me to post this in here. but i found some stuff for MS'n'EDIS as apposed to MS'n'S, for some of those people, just another way to control the spark that deals with out using a dizzy, may have been posted before, for those who would want to use it.

EDIS Hardware from Boost Engineering.
http://home.earthlink.net/~beanbooge...t_engineering/

From a fellow named James Murray.
http://www.jsm-net.demon.co.uk/megasquirtnedis/

Another from a Bruce Bowling.
http://www.bgsoflex.com/mjl/mjl_edis_summary.html

Perry Harrington
http://www.dainst.com/info/edis/edis.html

this was brough up, because a friend of mine has mentioned something about it for his Z car and i know Matt Dupuis has done something similar. just thought i'd share the info for thos who might be interested.

matt.

[nrvate]

... for those who read this and were wondering "what about the idle control valve?" ...

http://forums.turbobricks.com/showthread.php?t=6772

[The Aspirator]

I've been running for over 6 months with just an enlarged throttle body hole for the thumbscrew, works alright. But now that it's winter my cold idle sucks. It just needs to idle at 1500 rpm while cold to be smooth, so I've gotta keep my foot on the throttle or else it'll die. Soon enough I'll be installing some sort of fast idle solenoid that shuts off when the engine is warm enough.