This guy redesigned the original MS board to incorporate the relays onto the board and he designed it to be waterproof

This should be perfect for our cars for those that want to mount the ECU in the engine compartment without resorting to tupperware


MiniMS waterproof and on-board relay Megasquirt

Mike, does anyone sell a complete and test Megasquirt unit?

a guy was selling completed and tested Megasquirts (documented) on eBay a while back...good deal at $300 or so that he was asking.

I think if you do a search here, you can find the topic.

Mueller,

I have read about Megassquirt here, but I am not sure I know what it does. Is it a compleat replacement for the original ECU? Does it use all the old senders? The version with the relays, does it replace the relay board directly?

If there is a thread that discusses how this works please point me to it.

Thanks again

-Pete

There is a thread here, use the "search" button (Luke!).

In short--it is a build-your-own ECU. It can be configured to work with stock injectors, and a few of the stock sensors. Pretty much air temp and head temp. RPM is read off of the ignition points (or whatever points replacement you have), load is read by a solid-state MAP sensor, throttle position by a resistor-type throttle position sensor. You have to do some creative adaptation to fit a TPS to our throttles, because they open backwards to most.

It is almost infinitely configurable and programmable--they give you all the source code.

--DD

lets say you have a carb cam. can you make this work with lets say two throttle bodies? would this be any more effective? or would it just look cool? could you use old carb bodies for "injector bodies" ?

two tb's would have to have some wierd linkage.. and some wierd intake plumbing..

Too much work for not much result Im guessing.

Andrew

Waterproofing does not solve the temperature problem. The microprocessor and other components on the MS board are not rated for under hood temperatures. They strongly recommend NOT to mount the MS in the engine compartment several times in the manual.

From the manual:

"The limitation is the 68HC908GP32 processor itself (the part is rated to +70 degrees C), as well as other components like the MC33151P FET driver, MAX232 chip, etc.. They are all limited to the commercial temperature range of +70 degrees C. maximum."

Companies like PMO sell throttle bodies that bolt right on just like carbs. Carb bodies would work too but carbs cost too much, and the worn out ones are worn out in places that will hurt FI also (air leakage around butterfly shafts).

http://www.mini-ms.com/images/mpx4250.jpg

I hate it when that happens.. the mounting holes are off. Why is it that those things happen so much in PCB layout?

You can make it work, at least to some extent. You can use the carbs as throttle bodies if you like, but you'll have to machine injector ports in them.

It can all be done, it's just work.

--DD

This is exactly what I am going to do.


I have already run the MS with the stock intake setup.

I am modifying my engine, instead of carbs, I am going with weber throttle bodies...48 IdA's?


it is carb bodies, drilled out for injectors. mounts on the carb intakes. should work fine...

I will let you know in a couple of months...Oh yes, throttle bodies are a little less expensive than carbs..link below
throttle bodies

So if the temps in a 914 engine bay are higher than the MS is rated, then where have folks been putting the MS that have already built and installed them?

From the looks of it, the MiniMS is still a "build-it-yourself" system like MS. It's just a different physical configuration. Is this correct?

Fiid is running his in the stock ECU location, I ran mine in the trunk, I think Dave Hunt is running his inside the cabin.



yes, but the added feature of the MiniMS is that the relays are on the board vs. being on a seperate board which then must be wired to the MS. The MiniMS has a much better connector...I never did like the DB25 connector.

I'm mounting my MS inside the cabin. I'll probably put it behind the backpad or under the armrest. I want to keep it close to the engine compartment but be able to get to the programming connector and LEDs easily. I need to mount my wbO2 controller nearby as well.

Man I like the sound of the dual Weber TB FI setup with a MiniMS running the show! Throw in a set of Nickies and I'm wondering what kind of HP a 2.0L would be putting out.

I just finished soldering together a MS board. Just from the picture on the main page, it looks like that PCB puts the components, in general, much closer together than the MS board. I wasn't snipping the leads in between soldering components, and it was getting to be a forest of wires on the back side... I imagine that board would be impossible to solder together with out snipping leads after each component... At least it doesn't look like anything is under the MAP (boy was that fun trying to get an iron in there)...

Any ways, looks cool!

-Kevin

How hard is it to successfully solder together a MS if you've never soldered circuit boards before? Do you need special equipment other than a regular soldering iron?

It's not that hard, but you won't be happy with the results if it's your first attempt at soldering. Soldering is a skill and it takes time to master it. I've been soldering for 20 years (since I was 6 years old, maybe before that) and it still takes me some time to do a nice job.

My advice would be to buy a decent soldering iron (Weller) and practice on some other things first. Go to HSC electronics and buy a kit or two, and build them. It's actually fun when you have the right tools.

How to pick a soldering iron:

Don't use a soldering gun, and don't use acid core solder either.

You need a soldering pencil, preferably one that has built-in temperature control. The super cheap ones from Radio Shack just keep getting hotter the longer you leave them on and don't give you as good a quality of solder joint as the good soldering irons do.

Weller makes a lot of nice soldering pencils and most of them have temperature control to maintain a constant temperature and add extra power as needed. That way you can use a higher power iron so you can work quickly but you won't roast the little components on the board - that is the beauty of temperature controlled irons.

I use a Weller WTCPT soldering station. It has a base with a beefy transformer in it (more power!) and a separate soldering pencil that is small enough to use for building a kit like the MS. It's about $100.

Weller also makes soldering irons that do not have the separate base unit that should be considerably cheaper (maybe half the price?). One of those would probably work fine as well, but most likely will not be as powerful or as compact and easy to use.

For a beginner, get a low to mid priced iron, and work your way up. But spend the extra money and get one with temperature control, you'll thank me later!

For solder you want 60/40 tin/lead rosin core solder. Available at Frys, Radio Shack, and a lot of other places. Get the thin stuff, it's easier to solder small leads with.

I'll second the good soldering iron comment. After decades of using cheap irons and getting only OK results, I finally went out and bought a temp-controlled Weller and was amazed at how much easier it was to get good solder connections with it. Get a selection of tips, using a point tip for soldering components on a PCB, and a chisel end for bigger stuff (wires to switches, for example).

It's not necessarily, but a board vise (clamps the board at the edges, allowing you to hold it up off the table and get at both sides of the board easily) helps a great deal. Rather like an engine stand for circuit boards. Frys has these. If you're not a spring chicken, a magnifying lamp is also very helpful.

add a fan to the list...I normally just use a small box fan to suck the fumes away from the workspace.....special fans are available that have a filter.......

another important item: solder sucker for when you need to fix a mistake of too much solder or need to remove a component....

I like solder wick and I use it a lot. Use the solder sucker for big blobs. The solder wick helps you clean up leads and traces and get rid of every last drop of excess solder. For removing ICs and components with a lot of leads, solder wick helps a LOT.