So kiss it time for a ms3/ms3x sticky thread yet.

 

As soon as someone writes the content, yes.

I'll be updating my Megasquirt writeup to include the MS3 but it will be a while before I have the time to do so. Plenty of other areas of my website need the attention first.

 

Actually, much of the MS1 and MS2 write-ups apply to the MS3/MS3x. Besides obvious differences in wiring, there's also differences in the use of TunerStudioMS and tuning. So far, I've gotten my MS3 with MS3x expansion assembled to the point where it works perfectly fine on the bench.

My advice is to use the existing write-ups a basic guide, and note differences between the earlier units and the MS3. I'm going the extra mile with new Denso yellow-body RX8 and Bosch EV14 injectors, GM temperature sensors, and a NGK Wideband.

 

I don't know...I'd say that more has changed with MS3X than one sees at first glance. No more Zeal or LM1815 circuit, no more BAC modding, no need to add fan control, sequential injection wiring (twice as many injector wires), two different wiring harnesses now, etc.

It's different enough that I'm going to simply add an "MS3X" section to the writeup instead of trying to work it into the MS2/MS1 stuff.

 

Well, I'm def looking forward to it! I'm wrapping up a few things before I wire up my MS3X...

 

To be honest, I believe the information in the ms3 manual should be sufficient. Everything should be covered there for getting an rx7 running on ms3, and anything that isn't should be brought to my attention so the official manual can be improved.

Ken

 

The only gray area I've seen is the injector timing maps for sequential injection. They recommended starting at -360* BTDC for a piston engine, so I just divided it in half since piston engines work on a 720* cycle and ours is 360*. I'm taking a week of in July to work on the wiring and hopefully start it up, so we'll see how it goes. I'll try and post some pics when it's running. Between Aaron Cake's MS2 writeup, DIYautotune's writeup, the megasquirt manual, and the internets, I feel like I have a pretty good base cal. I'm just not sure what firmware to start with. Someone on the megasquirt forum was recommended pre1.1beta20, so I'm starting there.

S4 n/a with a S5 intake, LS2 coils in direct fire, and sequential injection on MS3X.

 

For firmware I would use the latest 1.1 firmware. We are close to releasing 1.1 anyway, so it's pretty stable.

As far as injection timing goes, we have changed our recommendation to 360 degrees as a good place to start for piston engines. For the rotary, I'd look up what your intake port's open and close are, and time the injection a little more than halfway between the two. Since the rotary doesn't have hot valves to squirt on and help vaporize the fuel, the next best thing is peak air velocity, which is usually around where I said.

After setting it there, you can tune VE with those values. Then you can adjust the injection timing. What you'll look for is the point where the injection timing causes the engine to run the richest, then you'll back off the VE table to get back to the AFR you want. Using this method will save gas too.

Ken

 

I now have an MS3X in my shop being installed on a friend's car and took some good pictures of setting up the harness for the CAS as well as all the internal jumpers on the MS. So as soon as I have some time, I'll be updating the writeup for MS3.

 

Right now, though, you can use the primer at diyaututune for the ms3's wiring and jumpers and aaroncake's programming and tuning pages on the ms2 to get you going. I was able to get my fc running using that information and the tables aaroncake provides (when he says the ve table is rich, it is very rich, like you can not blow the engine from lean condition rich).

What is different is the tuning software required for the Ms3; TunerStudioMS. Most of the ms2 programming applies to the ms3, except for the obvious i/o and sequential settings, which can be found at the ms3 site and diy.

 

The tuning software is only different if you're coming from a really old MS2 firmware... like 2.1.x series.

The MS2/extra 3.x.x firmware requires Tuner Studio.

Ken

 

And that's what I need to fix as well. The MS2 stuff in my writeup is from a very old firmware and doesn't line up with the new firmwares. It's just a staggering amount of work to recreate all the screenshots and tables...also I don't have an MS2 around.

Yes, no question that my fuel tables are rich however that's on purpose. I've seen a lot of beginners struggle to start a car with a table that's too lean because they are thinking in piston engine terms. Thus the tables guarantee a startup but are also universally rich across the board since it is safer to start rich and lean out than the other way around.

 

Note quite, but it's pretty close. I did go with a higher frequency for the BAC valve, and there are i/o options for handling things like the auxiliary port actuation (reused an emissions solenoid to direct air from the air pump--works great).

I'm not complaining about that; not at all. I'd rather slowly bring the a/f ratio from rich to just right than go too lean, blow the apex seals, take the engine out, ship it, have it rebuilt, shipped back, re-install in the car, and do lots of cursing and second-guessing along the way.

Using the logging function and reviewing it with the megalogviewer really makes tuning the fuel map a snap. Just drive the car, review the log, see where it's too rich or lean, change the fuel map. Drive, rinse, and repeat as needed.

 

There is one thing that caught me.

In TunerStudio, when I imported the AFR table (for the AFR targets in closed-loop mode), the software incorrectly translated the numbers to lambda. So I was running rich at cruising speeds and too lean at low-load, etc. To fix it, you simply calculate lambda=AFR/AFR stoich and enter them in the table (you can highlight multiple cells and set a value for them).