Oochi

Hello, I got all (most) of my MS3X parts in and I have started the build! This is for a 90 with stock 1.6 btw. I figured I would make a build thread because I know I will have questions and don't want to screw this up, plus you guys know more than me. anyway, So far it has gone quite smooth. A couple things that I am confused about. I got the resistors in, then diodes, now working on capacitors. One thing I am confused on is I have a resistor in a baggy by itself labeled "BIP373 330o, 330QBK-ND" i know it is a 330ohm resistor, but i cannot find it anywhere in the manuals. I have been using www.msextra.com as a reference. Another thing is...I'm not sure what this means! Please review my progress and let me know what I do wrong, or any other recommendations. I will update this as often as I work on it. Will be during weekends due to college.

PICS:

WestfieldMX5

You're not following the correct instructions. You've already installed a bunch of components you don't need.
Take a look at my build how-to's. They work just as well on a NA (don't build the alternator circuit, it's not needed on a NA).

Oochi

well thats just great! would it hurt to leave whatever isnt needed in there? and are you saying to follow http://westfieldmx5.devocht.com/mega...egasquirt-ms3/ and http://www.megamanual.com/ms2/V3assemble.htm ? I was just following the directions that diyautotune sent me to look at.

Braineack

iTrader: (62)

it doesn't hurt anything to install it all, but frank's ms3 writeup you linked to above saves a bunch of time if you simply follow that component map.

Freaky Roadster

This is the set up brain sent me to build for my '95 1.8l

It does have a slight variation.

Oochi

Gahhh there are so many of those diagrams floating around for what and what not is needed. So confusing. Anyway, here it is as it sits now and until next weekend

Joe Perez

iTrader: (8)

To be honest, it sometimes amazed me that anyone who isn't an engineer manages to build a Megasquirt, given the state of the documentation.

Long story short: You can build the unit "fully" according to the primary documentation and nothing is lost. Since you are using the MS3X, your build will be particularly simple as you needn't bother with any of the old-style "hacks".

As to the quote in your first post, you are not going to be triggering from coil -ve. That applies only to cars with distributors and breaker-point ignition. (Remember, the MS project has its roots in the old-school American Iron community. They see nothing wrong with distributors, throttle-body injection, separate water fountains for brown people, and arranged marriage.)

Reverant

iTrader: (10)

I don't see a heatsink under the FETs. You can get away if you are only using U5, but not with that many. Oh, and you must not use nylon screws and nuts on the FETs that get hot.

Oochi

Wow. I can't believe i forgot to put the heatsink on. Double and thanks for the info on the nylon screws, i was thinking about that when i put them on but I thought i saw other pictures with them on there so I assumed it would be fine but i will change them this weekend. Appreciate the help!

WestfieldMX5

R1 and R19 are not installed on that map. You only remove R1 if you want to do table switching or launch control.
I'm not sure why R19 is not there. It's required with the TIP120 mod.
I'm sure Brain can explain the raison behind it.

Braineack

iTrader: (62)

I'm not sure I made that one. But if the MS3x is doing the idle, you dont need r19. And really R1 isn't needed IIRC.


This is the only I've made, but it still has more than you need:

WestfieldMX5

My bad, I forgot he used the MS3X for idle, thus no TIP120 mod and no R19 needed indeed (I just finished a 90-97 MS2 how-to, hence my mixup)

Oochi

So remove R1 and R19?

EO2K

iTrader: (37)

And that is what really gets me about the MS and why I paid Scott to build one. I want to do a carb -> EFI project in the future but figuring out the MS2 documentation is a bloody nightmare. I'm just glad you guys who DO understand it are willing to give advice/suggestions/abuse to help keep us noobs pointed in the right direction.

Good luck Oochi, I'll be watchin'

WestfieldMX5

Remove R19 and install R1. There's plenty ports on the MS3X that you don't need the R1 input.

Oochi

Amen brutha

Freaky Roadster

All the build confusion boils down to how good the MS really is. You can build it configured specific to your actual car or the general model or for a lawn mower. Fantastically versatile.

Oochi

so do I not need any of those 3 pronged transistors on the heatsink? Just r37 and r38?

Oochi

Also, the diagram brain posted above has only U3 and westfield's only has U7?

WestfieldMX5

Study this http://www.megamanual.com/ms2/pcb.htm
Look up the parts that you're not sure about and see what they do.
U3 is the opto-isolator, so if you need it or not depends on how you wire the tach inputs.

Brain's diagram assumes you use the opto circuit (U3) as crank input and JS10 as cam input as discussed in this thread.
My diagram assumes you use the VR circuit (U7) as crank input and the VR circuit on the MS3X asd cam input.
Same result, done differently.

The only transistor you need on the heatsink is U5. The rest of the parts on the heatsink are for the injector circuit, but you can leave those parts out because you use the injector outputs on the MS3X instead of those on the main board. IOW, everything you installed on the heatsink up to now, including R37 and R38, is not needed.

Same thing with the idle circuit, you use the one on the MS3X instead of building the one on the mainboard.
You really need very little parts from the mainboard.