DIYPNP Closed-loop Idle AC trouble
 

Ive been having a bit of trouble getting my buddies car idling well in closed-loop in general, but in particular with AC.

Car is a '93 1.6, all stock other than toyota COP retrofit and coolant reroute. Stock injectors, no turbo yet, etc.
DIYPNP (not setup for full sequential), GM IAT, and GM ECT.

The issue is that I cannot get the idle strong enough to cope with the compressor load. AFRs are pretty solid in the idle area of the map and Ive given it a plateu of even advance to let the closed-loop idle advance work.
This seems like a good case for using the "AC idle up" menu, but Im having trouble there as well. The AC switch input is connected to the microsquirt "Input 1" as documented on DIYautotune, but I dont see this input in tuner studio. So at the moment the ECU is blind to the AC being on or not.

Here re some screenshots of the fuel and ignition maps as well as the idle settings, but I will attach the MSQ too. Perhaps I am overlooking something?

Attachment 230063

Attachment 230064

Thanks in advance everybody :D

Do you have the AC circuit wired up as such:

it's really not hard. Say you have a '91.

Instead of wiring 1Q (the a/c switch) to Input 1 IN then back OUT to 1J, simply completeing a circuit.

You'd wiring 1Q to Input 1 IN, The input 1 OUT to PE1.
Then from PAO to 1J.

Now, when the A/C switch is grounded, the MS knows, it can bump up the idle, then ground the output to 1J.

That's a quote from another thread in this forum. If you don't have it like this the DIYPNP does not have AC control.

idle up duty adder -- make it 12%
idle up target rpm adder -- make it 100rpm

youre not telling the MS to do anything special when you turn on the a/c.


also what hector said, if you followed the diyautotune.com install docs, they don't have you actually wire up the a/c controls into the MS -- so those settings above would be moot anyway.

Actually the bold italics is what you said. Quoted from one of the multiple times you have stated the wiring needed for full AC control.

The way DIY has it wired up can be made to work but by being reactive as opposed to proactive, you will still get stalling issues at times. I don't see the setting there of minimum RPM for AC on but that is a big help in not stalling the engine. I also found 16* timing at idle helped a bit but YMMV.

Thanks for the replies.

Input 1 is currently wired up with IN connected to 1Q (the AC switch) and OUT connected to 1J. So it should at least be able to idle it up when the switch is on, even if the compressor is doing its own thing. The issue remains that I dont see the AC light in tuner studio lighting up when the switch is on. What input should I be using in the AC idle up settings? None of them worked.

I will get him to do the modification mentioned above to give the ECU control over the compressor though. That should be really handy in making the idle anticipate the compressor. Plus the little B6 would probably like the AC shut off above ~40% throttle. lol

As for the idle, the owner had told be before about idle issues when it was stock, and I completely forgot that he ever said that. We are thinking the general idle shittiness may be caused by IAC being a 200k mile, 24 year old, dirty, turd.

wiring 1Q to 1J simply grounds the a/c relay via the a/c switch; there's no MS involvement whatsoever.

The a/c switch simple goes to ground. you're taking that ground and sending it directly to the a/c relay. when you flip the switch, you send a ground to the relay, and turn on the a/c compressor/fan.


what you need to do is wire:

1Q to Input 1 IN.
Input 1 OUT to PE1

that will bring 1Q into the MS; safely through an input circuit

then wire a spare out, like WLED to 1J. This will allow the MS to then activate the a/c compressor/fan independently of the a/c switch.


see my DIYPNP wiring documentation: https://trubokitty.com/#/diypnpassembly