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.