MS2PNP Air conditioning idle-up
 

Been playing around with the closed loop idle control with a MSPNP2 and a '94. Works awesome, but the AC idle is definitely reacting to the draw of the compressor, not predicting it.

Is the ECU already wired for the AC idle up? Or do I need to wiring something from the AC button to the ECU?

Here are the default settings I have once I activate AC idle up:

https://www.miataturbo.net/attachmen...ine=1418956568

And the drop down menu choices for which pin I should use:

https://www.miataturbo.net/attachmen...ine=1418956568

https://www.miataturbo.net/attachmen...ine=1418956568

pop open the case, there is a knob in there to adjust the predictive idle up, its a hardware control not a software one.

This should help.

Perfect, thanks. This quote pretty much sums it up:

It was running on 3.2.1 yesterday, but it's now on 3.3.1. But does the older MS2 still have the potentiometer to use the AC idle up?

I guess I'll have to wire it, as the owner does not want it to be reacting to the ac draw, he wants it predicting it.

how is it wired now?

to be reactive, you need to wire the INPUT into the MS, and then allow the MS to control the OUTPUT.

it wont turn on the compressor until after you idle up delay. If it's not wired in this manner, I'd remove the delay completly.

We've unplugged the stock ecu, and plugged in the MS. That's how it's wired.

So you're saying the output is the compressor? And I need to lower the delay for it to catch the idle sooner?

is there any software changed I can make as to how much it raises the idle valve? Or is it purely hardware?

diypnp2 is different.

but change the adder%

Is this a V1.2 or V1.3 ecu? The a/c control is very different between them.

Good to know. If I had to guess it's a V1.2, it has the original 3.2.1 firmware and has been purchased for quite some time now. I'm guessing it'll say on a sticker on the box? Haven't looked at it yet.

But assuming it's a V1.2, have any insights?

Scott, adder% is a software setting or the hardware setting we've discussed? My question is how to make the AC idle up work, aka: what input/output pin to select, if it's wired in through the stock harness.

http://www.megasquirtpnp.com/docs/mspnp_g2_boardID.php

Looks like its a different rear connector between board revs.

For the adder percentage: If its a V1.2 then no software settings to configure. Just adjust the dial in the picture I linked above.

V1.3 default uses the table switch input. But can be changed with a jumper.

https://www.miataturbo.net/attachmen...ine=1419032937

Ah, so try setting idle-up output pin to table switch and if it doesn't work it's a v1.2 and I should open the box.

That's what I'm hearing.

You can count the number of pins on the front connector too

If it's the V1.2, you can set the a/c on idle bump by rotating the marked trim pot on the mainboard. We did it this way because it is simple for the end user to implement and works pretty well, and because that way it wouldn't use any I/O. However everyone wanted to be able to configure in software, so we changed it in V1.3. I personally prefer the older method, but it's not what you guys wanted, and we wanted to deliver what was requested of us.

Sorry to hijack the thread, but I recently installed a mspnp2 in my 1990. I'm having an issue with AC idle up always raising the idle even if AC isn't on.

Konmo, can you please attach a data log of the issue and a copy of your MSQ?

Here is my current MSQ. I already turned off the setting and changed a few things so its not exactly the same tune as the log, but very similar.
It won't let me upload the log. Its under the max size. not sure what is happening.

https://www.dropbox.com/s/rowtmvnqcs...erbnb.msl?dl=0


Not sure if I'm allowed to do this, but here is the log. I had to upload it to dropbox. I have the high idle since after cranking and I turn off ac idle advance around 4 min into the log. You can see my idle rpm goes down to my set 950

Do you have a V1.2 or V1.3 board? If it's a V1.2 board, the idle up circuit works on its own and avoids the tune settings.

Hmm I'm pretty sure it's a 1.3 board. It had a jumper set on the tableswitch pins. I had read that 1.3 boards came like that.

V1.3s are green, V1.2s are red.

in that case, I have a V1.3 board.

Is this thread dead? I got my MS2PNP AC Idle sort of working but I think the delay-up is not working well.

Well, this is the first anyone's posted in this thread for nearly two years now. What board version is this, and can you post an MSQ and data log?

Sorry for the delay. I had a Board exam yesterday and I had to fall off the grid for a couple of weeks to get ready for it. Today I made the Data log. In Open Loop Idle the AC kind of work but sometimes the car stalls when slowing down or stopping, with or without the AC on. With Closed Loop the car runs fine and doesn't stalls without the AC (with the AC the car stalls). I know the valve is working because I can control it with the "CAN bus.

PD. I'm using this site: megamiata.blogspot.com/2014/12/closed-loop-idle.html as a guide. But the car never the car idle never oscillates even with the gain to 200%

Please post the complete MSQ file - the problem may not be on that screen.

Here it is. The map is kind of crazy because I'm completely new to this. I've run Autotune a couple of times but I made a couple of changes trying to fix the rev dips and engine stalls (in "Open Loop") when going to neutral. But that got fix with the CLI "Soft Landing".

Try using some extra spark advance to "catch" the idle in the main spark table.

Thanks! I did as you recommended and that fixed the stall issues. But the AC still kills the engine. I don't know why the CLI is so complicated to adjust. I thought that every Miata IAC valve had to be the same and gaining control of it would be easy or well documented (since there are 100s or 1,000s if not more MegaSquirt Miatas). It is as if the ECU doesn't receive the signal that the AC is on because it never rises the RPM. But the compressor and everything else engages normally. I think I'll go back to the stock ECU while I gather the pieces to make my own turbo kit and take it to the local Tuner. But I'll really miss the couple of Ponies the MegaSquirt added :sad2: I just wanted to have everything sorted (as recommended by most users here in the forum) before adding other variable to the mix. I just hope the Tuner is able to fix it. Here in PR Megasquirt is not as popular.

Uninstalling the Megasquirt I just noticed jumper J5/AC is open. Is this supposed to be Jumped. I still can't get any response from the AC Idle Up.

This is My board.https://cimg4.ibsrv.net/gimg/www.mia...7328043399.jpg
https://cimg6.ibsrv.net/gimg/www.mia...ec7309fcba.jpg
https://cimg9.ibsrv.net/gimg/www.mia...3c0e58f04e.jpg

AC Idle Up
 

Hi David, did you ever figure out the magic combination of Closed Loop Idle and AC Idle Up settings? I am having the same problem as you. My car is a 1994 1.8L NA running MSPNP2 with MAF delete, normally aspirated. I did not look at the J5 jumper on my board, but I have the same black jumper between the PE1(TS) and AC ports.

Basically I have a good Open Loop Idle tune, and my Closed Loop tune is okay but the ECU cannot "catch" the falling RPMs when I turn on the AC so the engine stalls. Here my baseline CLI settings and I've been playing with each setting to see if it would activate the AC rpm adder in the AC Idle Up menu, but so far no luck.

Anyone else who has a suggestion - feel free to chime in. I am in the trial and error phase of CLI and I can always switch back to my solid OLI settings if my latest experiment does not work.

Its working
 

Well I got it to work. But I'm no expert. I changed a lot of things in the base tune supplied by megasquirt. Below are the ones I think got it to work. But please remember I really don't know much about what I'm doing here. The J5 jumper is meant to be left open (as advised by the diyautotune support team). Regarding CLI I followed Megamiata blog to guide me. In my case I think the main problem was that in the version of Tunerstudio that I have there is a setting called "Idle-up min Rpm" and the description says that it is the min RPM for the compressor clutch to engage. But it really is the min RPM for the "AC Idle up" to work (which I think is useless but I'm no mechanic) and I had it set to 950 RPMs while my car Idled at 825 RPMs Aprox which meant that "AC Idle Up" function was turned Off while idling. After making the changes in the images below (time advance, PWM voltage, ETC.) I set it to "Idle-up minRPM" to 100 (as advised by DIYautotune). Then ran "Autotune" while Idle with the AC on (giving it a little help with the throttle the first couple of times because I've always ran Autotune with the AC off) until Autotune fixed the map according to the extra load on the engine. It ended a little richer in idle but now it works. It stills stalls from time to time when turning the AC on, and the car hesitates a little every time I turn on the AC (The support team said that the MSPN2 is not powerful enough to delay the time of the AC compressor clutch to activate). But its working. Remember that I have a '99 Miata things could be different in your setup. In my case the Idle Up input polarity is High (I noticed yours is set to low) I don't know if this changed from NA to NB but maybe that could be the problem. Hope this helps.

AC Idle Up
 

Hi David, thanks for the fast reply. I am just getting familiar with TunerStudio and will search for the maps you displayed. It was helpful to see what your AC Idle Up and CLI settings are too. In the spirit of the MiataTurbo forum slogan, here's a fat cat picture as a thank you!

Glad to help :bigtu:

FWIW, on my '95M v1.2 (RED motherboard) I had to turn the potentiometer almost all the way counter clockwise to get mine to idle w/ a.c. If i turned the dial all the way CCW, car would idle ~1750, but a tick less (vertical engraved line) and car idles nicely w/ A.C. ~1K RPM, still needs a blip to get going no matter what the dial's settings.