Learn Me: Megasquirt.

So I've read a few basic articles about MS, did some poking around on the google. I feel like I have a pretty good understanding of how the box itself works, but less so when it comes to an actual conversion. For my application, I'd be looking at replacing a K-jet system.

So how hard is it to set up MS? I've got a pretty good list of parts I'd need to replace the K-jet, and I know a guy that will make me a new engine harness for ~$150.

MS2 v MS3, would MS2 work well enough for replacing a K-jet system on a mid 80s 4 banger? What about Microsquirt? I like the size and the price, but read online that it's more for ATV's and the like. Can I set up MS to run only fuel and keep the stock ignition system?

Most of all I'm wondering, if there's someone who has already set up MS for my engine and I duplicate their set up, could their programing be transferred to my box? Is it a sort of thing that is tailored engine by engine, or is what's good for the goose good for the other goose?

The most important question: Can I setup MS for NA now and go turbo later?

Thanks in advance!

MS2 will do full sequential and COP on a 4 cylinder.

Ixnay on the Micro.

Why in dog's name would you keep the stock distributor? That is like the tail wagging the dog!

Using someone else's tune or MSQ is like wearing someone else's underwear, sure you can do it, but why, and are you sure you want to? They don't fit and smell funny....

NA Turbo or spray can all be done. You need to plan though, make a list of all the options you want and build it up that way. Making changes later on can mean a complete redo or require an upgrade without the planning thing. Look at the output port matrix and make sure you can do the options you want with an MS2.

Read everything you can find, stick with Extra code, be fore-warned the documentation sucks. DO NOT attempt this on a DD that needs to run by monday AM. I'd recommend having an experienced MS'er hold your hand as there are many pitfalls (especially with the install). The first pitfall is to not use low impedance injectors without a P&H board. Use a 36 - 1 tooth crank trigger wheel with wasted spark for simplicity. I prefer the v3.0 board because I can build it what ever way I want.

http://www.msextra.com/doc/index.html#ms2

I used a microsquirt on my 3SGTE as my first MS project a couple months ago. It's running fuel and spark but MICRO won't run certain IAC's. You could probably run your distributor if you wanted or batch fire coil on plug ignition. Don't worry about just diving in, the community is super, most of my noobish questions got answered in hours of being posted in forums.

Interesting. This is a step I was thinking down the road for the 924.
What 4 cyl 80's car are you looking at performing this upgrade on?

I just bought a car with an incomplete Megasquirt setup so I'm at this "start from scratch" learning point as well.

It can be a bit intimidating trying to figure it all out when you're starting from the point of zero.

In my case I have a 2.0 16V VW (9a) engine in an '86 Golf. Megasquirt II Ver. 3.0. It was previously a CIS 8V car, so it has an aftermarket fuel rail and digi injectors now (I think), but the 9a did not have a crank trigger wheel so it's still feeding off the hall sender/distributor for signal. Stock automatic Passat 16V TPS. No wideband O2.

It apparently idled once, but that's it, so I'm essentially going to treat it like it was never installed and verify everything from step one. Just figuring out what step one is is the tricky part. ha.

Mike924 wrote: Interesting. This is a step I was thinking down the road for the 924. What 4 cyl 80's car are you looking at performing this upgrade on?

Mercedes M102 single cam 2.3. The K-jet is working okay, but the miles are getting up there. If there was a OEM EFI option for this engine, I'd go that way. But it was only ever installed with K-jet (Ke-jet if you want to get specific). So it looks like my options are carb or MS. I think the engine would run miles better with a modern EFI system. I'd like to go as simple as possible, maybe batch fire? Every EFI Volvo I've owned has been batch fire, never really missed anything. Or maybe that's like replacing a typewriter with a "word processor."

Why not keep the dizzy? It's a Bosch system, and works just fine. Integrated fuel/spark would be a whole new world for me. haha.

bentwrench wrote: Using someone else's tune or MSQ is like wearing someone else's underwear, sure you can do it, but why, and are you sure you want to? They don't fit and smell funny....

If I may say, that idea seems really silly. Why not use someone else's work? If it RUNS, then you have something to work with.

More like needing a pair of gloves, and finding a nice broken in set at Salvation Army.

Best advice that I got from a racer, start with something someone else does well with. Works as a calibrator, too. I have never once filled in a full calibration myself. Not even close.

There's no reason not to use someone else's work if they are ok with it, and it works.

RoughandReady wrote: So I've read a few basic articles about MS, did some poking around on the google. I feel like I have a pretty good understanding of how the box itself works, but less so when it comes to an actual conversion. For my application, I'd be looking at replacing a K-jet system. So how hard is it to set up MS? I've got a pretty good list of parts I'd need to replace the K-jet, and I know a guy that will make me a new engine harness for ~$150. MS2 v MS3, would MS2 work well enough for replacing a K-jet system on a mid 80s 4 banger? What about Microsquirt? I like the size and the price, but read online that it's more for ATV's and the like. Can I set up MS to run only fuel and keep the stock ignition system? Most of all I'm wondering, if there's someone who has already set up MS for my engine and I duplicate their set up, could their programing be transferred to my box? Is it a sort of thing that is tailored engine by engine, or is what's good for the goose good for the other goose? The most important question: Can I setup MS for NA now and go turbo later? Thanks in advance!

Check the forums for your particular car as there may be someone there that has done the conversion already. Also msruns.com might have some information on running cars and their settings. Adding a turbo or making further changes later is certainly possible, you have complete control over the ECU hardware and software configuration.

The simplest conversion is to run megasquirt in a fuel only configuration and leave the stock ignition solution in place. This will alleviate having to try and tune both the ignition and the fuel from scratch. Getting an MSQ or fuel table from someone else can help, but you'll still need to adjust them to your particular hardware as you may be running different injectors or other changes (cam, intake, etc.). If you can use a donor MSQ to also tune ignition then that is just gravy.

The hardest part (after sorting out the wiring and sensors) is getting the engine started and idling and that just takes trial and error. Don't forget that the start settings are temperature dependent so you'll want to start tuning these settings at different temperature ranges. Lots of info available on this on the web. Many tune by setting it to 1.0ms and adjusting from there by .1ms increments until it starts, note the ambient temp and place that in the appropriate range. Let the engine cool and verify that setting works the next day. No matter what you'll want a good battery and fresh starter before going this route.

Once it tries to start (runs for a second or two before dying) you'll have to adjust the After Start Enrichment to keep it running.

Make one change at a time. They are dependent on each other and changing them both at the same time can drive you absolutely bonkers if you go too far, which is easy to do.

Once idling, you can slowly start to tune the fuel map using the autotune feature in TunerStudio in combination with your wideband O2 (these are almost a requirement for tuning) by slowly revving the motor from idle and holding it in certain cell ranges in the fuel map to allow autotune to adjust those cells. If you're starting with a a table from someone else, then this may not take very long since it should be fairly close and you can skip straight to road tuning. If you're working from scratch you'll need to finish free revving to get the fuel map close so you can start slowly puttering around your neighborhood to further tune the fuel map with a load on it. The amount the fuel map changes in those initial cells should give you an idea of how far to scale the rest of the base fuel map to get it fairly close so you can finish fine tuning the map with Autotune.

Once that base fuel map is sorted then you'll want to work on Acceleration Enrichment (think of a power valve on a carb) to help improve throttle response. There is a great article on DIYAutotune.com about AE tuning. IF you can swing it, then tuning on a dyno can help a lot here since you can run the car at nearly any speed and throttle position without much hassle.

As for which version to use? I'm not sure Microsquirt is of any benefit except to those that don't have room to install the already relatively small MegaSquirt ECU box. If there is a MSPnP option available, that might make the most sense, check DIYAutotune.com for more info on that. MS1 is well documented and works well for most basic CIS conversions, plus they are fairly cheap. MS2 is slightly faster with more features and has become the defacto "standard" for many builds. The nice part is you can upgrade an MS1 to MS2 by replacing the CPU with a $100 CPU daughterboard and adding a couple of wires. MS3 is awesome and will do even more, but it is expensive and quite honestly is more than most need for a simple fuel or fuel and ignition conversion.

No matter what version you choose, make sure the wiring is properly configured and installed. Many, many problems with MegaSquirt are related to poor wiring connections. I would also go with the MSExtra code base to allow more options and available configurations. A Wideband is basically a requirement, choose your poison there, lots of options available. I would also pony up the money for TunerStudio/MegaLog Viewer, they really help with tuning, plus you can tune with your smartphone/tablet via Bluetooth or WiFI.

In reply to RoughandReady:

MS is batch fired, there are two injector driver pairs. So you would run 2 cylinders off one injector driver. There are options for going sequential, but that would require more hardware and ignition control.

I will watch this as well. I have an 86 GTi 8v with CIS-e. And while it runs ok somehow I think it just would be "better" with a modern EFI controller running things.

RoughandReady wrote: So how hard is it to set up MS? I've got a pretty good list of parts I'd need to replace the K-jet, and I know a guy that will make me a new engine harness for ~$150.

That's a very good price!

MS2 v MS3, would MS2 work well enough for replacing a K-jet system on a mid 80s 4 banger? What about Microsquirt? I like the size and the price, but read online that it's more for ATV's and the like.

While the MicroSquirt was designed for ATVs and motorcycles, there's no reason you can't run it on a car. I installed one on a 2.3 powered Mustang as part of the original beta testing, and it's been used on V8s. A MicroSquirt should work just fine for what you are planning.

Can I set up MS to run only fuel and keep the stock ignition system?

Certainly.

Most of all I'm wondering, if there's someone who has already set up MS for my engine and I duplicate their set up, could their programing be transferred to my box? Is it a sort of thing that is tailored engine by engine, or is what's good for the goose good for the other goose?

It could if your engine was exactly the same and you were running the same hardware and firmware. Otherwise, the tune may be a starting point, but will need some final adjustments. And you can't always be sure of the quality of other peoples' tunes on the Internet. With MegaSquirt being one of the most affordable ECUs out there, there are a number of people who post tunes who didn't really have the budge to get things really dialed in.

The most important question: Can I setup MS for NA now and go turbo later?

Absolutely! Just be sure the MAP sensor is sized for the amount of boost you plan to run later.

In on this.

The research I've done seem to indicate that I need to step up to MS3 if I want to control any sort of VVT. True or not?

In reply to xflowgolf:

This might help: MSRuns VW section lots of info there that should help.

calteg wrote: In on this. The research I've done seem to indicate that I need to step up to MS3 if I want to control any sort of VVT. True or not?

You can do it with the MSExtra code and an MS2 with a relay control add-on.

You might also get on some of the Volvo sites like Turbobricks since people over there are replacing K-Jet and running +T on Volvo 4 bangers.

calteg wrote: In on this. The research I've done seem to indicate that I need to step up to MS3 if I want to control any sort of VVT. True or not?

Any MS variant can be set up to control on/off VVT. MS3 can control continuously variable types as well.

In reply to MadScientistMatt:

Is there some big downside to Mircosquirt over MS2 or 3? I feel like your average modern ATV or motorcycle has more technology on it that this old tractor engine. It doesn't even have hydraulic lifters. It seems like most of the parts needed can be robbed from a Saab 900, the injector spacing is the same as the Merc.

NGTD wrote: You might also get on some of the Volvo sites like Turbobricks since people over there are replacing K-Jet and running +T on Volvo 4 bangers.

I'm on TB. There's a local member that went MS on his 244, hopefully I can get him to help me some with this. This K-jet and Volvo k-jet are pretty different. Mine seems to be a fair bit more complicated. At least it has a lot more wires to deal with.

RoughandReady wrote: In reply to MadScientistMatt: Is there some big downside to Mircosquirt over MS2 or 3? I feel like your average modern ATV or motorcycle has more technology on it that this old tractor engine. It doesn't even have hydraulic lifters. It seems like most of the parts needed can be robbed from a Saab 900, the injector spacing is the same as the Merc.

Not much. Here are the downsides to the MicroSquirt, such as they are:

1. No stepper IAC valve control. You can use a PWM type valve (or none at all).
2. It doesn't have current limiting for low impedance injectors. You can use high impedance injectors, or injector resistors.
3. A MicroSquirt does not have quite as much I/O as an MS2 that has been modified to bring out all available I/O, but it has more than an out of the box MS2.

MadScientistMatt wrote: 1. No stepper IAC valve control. You can use a PWM type valve (or none at all).

dumb question. what's "PWM" stand for?

Microsquirt is just a smaller version of MegaSquirt. Very little difference other than most people are more familiar with the "normal" or "standard" versions and I'd recommend that since most of the online tutorials and hardware mods are written for the standard V2.2 or V3.0 boards. No reason to make things harder unless you have to.

http://www.msextra.com/feature-xref.html

The K-jet in your Mercedes is likely more similar to the K-jet used in the Porsche 924 (the Audi motor used in the 924 was originally developed by Mercedes for Audi anyway).

For a MegaSquirt conversion you'll toss most of the engine wiring anyway with the exception of the ignition, starter and alternator wiring. Watch for safety interlocks on the fuel distributor that might cause a lack of ignition firing.

The MegaSquirt harness you'll build and install will be separate. You'll want to find a TB that has a TPS sensor or add one to your existing throttle body. Install the Intake temp and coolant temp sensors. Remove the CIS injetors and install your own injectors and fuel rail (is there one that will fit close enough to work? If not you'll need to build one and add a vacuum referenced fuel regulator).

In the rear, ditch the accumulator (sell it to someone else) and run the stock CIS pump.

Make sure you use EFI rated fuel hose and proper fittings to avoid leaks.

To fit the injectors in place of your CIS units depending on the size of the CIS adapters, look at VW or Audi EFI injector adapters. Some have machined the plastic ones to fit Bosch style injectors and seals with some success.

xflowgolf wrote:

MadScientistMatt wrote: 1. No stepper IAC valve control. You can use a PWM type valve (or none at all).

dumb question. what's "PWM" stand for?

Pulse Width Modulation.

not sure of the specific signal that the MS outputs, but say it's a one second signal. On .1 off .9 is 10%, .5on/.5 off is 50%, 1on/0off is 100%. With width of the pulse is controls how much it's on.

CIS cars typically have the Bosch style idle bypass solution that leverages ambient temp to alter the size of the aperture. As long as they are working and are provided 12v, its usually sufficient.

If however you wanted to have more finite control over idle speed, then you would use a newer style solution that uses a stepper motor that requires a controller to open and close it at will in very specific amounts. Great for cars with A/C among other things.

This might help:

http://www.megamanual.com/v22manual/mtune.htm

My CIS system uses the pretty standard Bosch IACV that came on later CIS Volvos and Bosch LH-jet (until or through 2.4, can't remeber). Some have 3 pins, some 2, some have a little adjusting knob. The difference between the Volvo and Merc parts seems to just be round pins for Merc and flat pins for Volvo. Seems to be a loaf of bread. I'm not even really sure if it communicates with the Ke-jet computer.

I don't really need a fine control of the idle. It's getting old and had never really idled where it's supposed to or without some coughs, weezes, and sneezes. If it had a constant idle at the correct rpm, I'm happy. The car will be a daily driver, so I think simple = better. Even a MAP is pretty new, i'm more used to MAF's and air flappers. haha.

I thought the CIS fuel pump ran at a pretty high pressure (like 90 psi or something?), maybe an LH pump or a Walbro or something might do me better?

As for a TPS, do I need a constantly variable kind or can I use something like later Volvo 240s had, where it's basically 3 microswitches in a box?

Might be a stupid question, but what do I really need to run the engine fuel wise? CIS seems to have so many redundant and overlapping parts. I have less experience with modern-ish EFI than I do with K-jet (all my cars have been old as dirt). So I need a MAP, TPS...RPM, temperature, idle control?

OP, mind if I ask some probably basic questions here about the MS implementation I'm trying to set up, or would you rather I start a separate thread?

bluej wrote: OP, mind if I ask some probably basic questions here about the MS implementation I'm trying to set up, or would you rather I start a separate thread?

Do it, I need to learn too.