NefMoto

Yo,

So my idle is mint.  14.7:1 with a little walk to 14.9/14.6.  Idles solidly at 800rpm (as I requested).  Vac is -20.

Turn on AC and it lifts up to just about -15~ vacuum and still idles well.  Turn the blows up full and vac bounces hard between -15 and -10.  Really rapid oscillations.  Idle is still solid at 800rpm but the gauge jumping about makes my OCD cry.

If I lift RPM up slightly with the pedal, it sits solidly at -15 vac again.

TL;DR:
> This is for ME7.5.
> can I bump idle RPM with AC on (I checked the FR and can't find anything)
> should I just make idle RPM higher because summer and AC is always on
> do something else?
> deal with it

My ME ECU has something called NSACTM - Desired idle speed with A/C on, it is set to 840 rpm across the whole temperature range. The regular idle target at warm is engine is 750rpm.

MED9?

The MED9.1 FR for TFSI has the description of NSAC module from page 432 on, the table NSACTM is mentioned there. Can't be bothered to check if that's the same as in my ECU..., but looking at the output variables (nsolac) seems like the thing you are after.

I'll check the FR when I get home and check the defined HN file I have for it.

I doubt it'll be there.  I should have clarified in the OP, this is ME7.5.

Oh, right... No, so mine is not MED9, ME7.9.10.

Still have this as an annoyance. 

The motor has a lightened flywheel.  Idle is smooth at 860rpm and lambda is 14.7.  Confirmed with a gauge too.

Vacuum is steady (could be slightly steadier, but I'm nit-picking) at -20.  Attached is a log.  First period is natural idle.  Next, I add heaters, then headlights then AC. Then remove AC, headlights and heaters and let it return to a natural idle.

Also quite a big jump in AFR when I turn AC off, not sure why that is either.

So first step:
How do I smooth out vacuum when AC is on? It gets worse when I use PS.

Next step:
How do I bring AFR back down to 14.7 when just restarted and not in regulation.

Third step:
How do I stop the massive AFR spike when I turn AC on/off?

NSACFS for ME7.5.

Injectors and MAF stock?

with the lightened flywheel and lack of stored energy compared to a stock one, could you need maybe to adjust the torque reserve maps?

I did, but it didn't do much.  More?  I tried 150/300%.  Nothing. :(

I can't see much on idle timing either.  Or wonder if the throttle PID isn't good.

before you go messing around with the throttle PID, check and see what happens to AFR with the AC off but when the fans kick on to cool the radiator. A very common issue is the fans wear out and start pulling a high load but not enough to burn the fuse. check the fans and see if they spin freely. Also check to make sure your battery isn't weak and the alt is putting out correct voltage. I suspect the fluctuations in AFR you are seeing is the ECU adapting to the change in load. One thing i did replace that made a world of difference was the cable connecting the Alt to the battery.

I must say I am running with a light flywheel ( 7.5lb SPEC), along with light weight non underdrive pulleys and fluidamper balancer and have never messed with the torque reserve maps though and I don't have the problems you are having. But I did have similar issues kinda and thats when I started checkign the stuff I suggested to you above.

Fans are fine, spin fine.  Battery is 6 months old and is a beast - biggest Bosch that would fit in the tray.  Passat 180A alternator too.  Done TB3 too.

AFR is fine tbh; it's more the boost gauge stutter.  AFR still holds true, it's just like the timing/throttle is jittering. 

your voltage seems low under load

Now that's interesting.

It's down at 12.3v once loaded up.  Sometimes drops as low as 12.0.  Could it be that?  Stock wiring though, not sure why it's dipping so much.  I'll go over the grounds but I'm sure alternator output should be strong like ox!

Id say it is definetly not helping the situation for sure.

Also the battery should bever drop below 12V i don't think. That is evidence of a bad cell usually

upon looking at your log again even at the start of the log with no load the highest voltage is 13.1 which should be atleast 14.1

If i were you i would have both the alt and batt tested especially since you did the big 3 upgrade.  it doesn't matter the rating or age if they are not working correctly you'll be chasing ghosts. I have heard of people getting remaned alts that were not outputting coorrect voltage because it was just rebuilt and voltage regulator was bad. I'have heard of people getting alts from the stealership and not to spec also. i have personally recieved brand new battery from Wallmart yeap...lol and it had a weak cell off the shelf..

Check to see that the voltage in the log matches what's measured at the battery with a multimeter. I remember the log voltage being ~ a volt lower than actual measured on a car without issue.

Battery voltage is 14.2.  Weird.  Wonder why the ECU sees so much less?

Also, I wonder if this is a hardware.  Come to think of it, I've just re-done the inlet and the MAF is now welded on a bend with no flow straightener.  I bet that it's my own fault that it's like this...

I had a battery once that showed good voltage but would fail a load test. What is battery voltage with the engine off? Same thing with an alternator. In the case of the alternator, the brushes had worn almost completly away. Not saying its your issue but it sucks when the simplest things make things seem way more problematic than they really are. both tests can be performed in like 5 minutes at your local auto parts store usually while still in the car.
 Assuming you checked grounds and voltage at the alternator and voltage at the battery while both are under heavy electrical load. Maybe it's time to check the resistance between the power lead ot top of the battery juction/fuse box and the pin for it in the connector for the ECU. it shouldnt have a high resistance.