Custom firmware modifications
 

After driving my car more than a full year on MS2, there are several issues that I wanted to correct, since I am a programmer and I have the source code, I fixed them myself. :)

Issue number one: You are driving and coast down. As you approach the idle region, the MS enters closed loop idle, and if you actually don't put the tranny in neutral or press the clutch in, the MS will try to maintain your idle speed, thus keeping the car moving and increasing the idle valve duty cycle to really high numbers...put it into neutral and you find yourself idling at 2500rpm or more.

So I connected the clutch & neutral switch to the PE1 input (switch tables) and changed the firmware to prevent the MS from entering closed loop idle if you are not in neutral and not pressing the clutch.

Watch for the "TRANS ENG" indicator. When it goes green, it means that either the tranny is in neutral or the clutch is pressed, thus allowing the code to enter closed loop idle.



Issue number two: When you heatsoak like I do in city traffic, you need to apply non-linear IAT corrections in low load/low rpm areas. Unfortunately the stock MS2 3.1.0 firmware applies this correction under all circumstances, whereas the older MS1 firmware did provide a way to taper down as the RPMs rise. So once again, I modified the code to do this.

Watch the lower right "Gair" gauge. As I increase the RPMs, the Gair is reduced to normal (ideal gas law) Gair value.



I've been testing the first modification for quite some time and it works really well, I did a first test of the second just today and though it does work, the non-linear corrections still need to be there beyond my hardcoded 2100rpm...I'll try 2500rpm and see where that takes me.

OMG I can't wait:)
You are truly awesome Dimitris.
If you want to test anything on any US cars I'll be your guinea pig

You deserve a bowdown Reverant. I would love to be intelligent to 'do' things like that.

Will you be making the code available for us numptys to use?

I never had #1 issue after I simply lowered the RPM in which PID is active.

#2 is cool.

Code will be made available once its tested out ok. #1 requires hardware mods (connect clutch and neutral switch to PE1), #2 does not. I had to delete some features (MAF, N2O, EAE) to make room for #2 as the processor flash memory is full.

More custom firmware awesomeness...

Different idle speeds if you have the A/C engaged! So you can idle at 800rpm without the A/C on, switch on the A/C and it will go to 1000rpm. It works on the bench, I need to test it on the car.

This is getting addictive!

Good we need a clever bastard like yourself to keep the MSII relevant.

The fact it's semi MX5 based mods is all the better

Any progress? I'm extremely interested in the Gair compensation. This is /the/ reason I regret not getting the 12 tooth crank trigger and running a MSI

It works all right. I plan on removing anything that seems to be out of place for a miata (several trigger wheels, nitrous, MAF) to make room for more features.

Ahhh I (seriously) daydearm about being able to do stuff like that.

Keep up the great work Reverant :)

That's really cool, I'm just jealous I'll never be able to use it with MS3.

I am really interested to see and use this with my DIYPNP...

:bowdown::bowdown:
Way to go D.

A little patience goes a long way. I want to give these to a few locals here to test them out as well first...it will be a lot easier to debug locally than over the interwebs.

Any ETA? (not being pushy, just curious:D)

Said two first mods are already done. These two (clutch/neutral and IAT corr) are already on my car.

I *LOVE* the clutch/neutral modification. I can let the car in gear in slooowly moving traffic in 2nd/3rd gear and it moves without touch the throttle, and at the same time the CL Idle doesn't activate which means you won't find yourself with a 2k idle once you go in neutral. Also if you frequentuly find yourself with a 1500/1800rpm idle without knowing why...this will probably fix it. I used to have this issue, and I've NEVER had it eversince I did this mod. Hardware mod is required but its easy.

I really haven't stress tested the IAT corrections as I can't find a suitable place to WOT test it during the day where I move to the shop and back (roads are busy). The IAT correction value may need to be readjusted so I would like to be able to provide a suitable value.

I still haven't modified my own ECU for the A/C system (yes, a hardware modification is required). I will once a find some free time (lol), but it does work (I tested it on a spare ECU I had laying around). I want to completely change the way the current A/C scheme works in light of this.

These 3 functions are the ones IMO that will make an MS not just better but great in the miata.

The car drives good as it is, but the a/c and stop/go cruise do remind you that it is a modified ecu. Tuning gets close to ironing it out, but you can still tell.

I did the A/C mod on my own ECU today, after swapping the MS3. Watch how the "target RPM" gauge on the lower left changes from 800rpm to 1000rpm when I press the A/C button.

I want this and the AIT corrections mod. You have this in a MS3 firmware package?

MS3? Aaaah, the great mystery that is the MS3. Well, you see, the MS3 firmware isn't open source yet....I begged for the source on the msextra forum, so that I could add a second "thermo" fan option, but alas, I felt like shouting in the desert.