I did a bit of tuning, and got the idle AFR good (as in, in the vicinity of 14.7) down to about 600 RPM. There were little things I had to figure out, like that when you turn off idle control, you also need to go into test mode and force the IAC closed or else it will just be stuck at the last position it was. Small stuff that's really obvious in retrospect.
Anyway, the RPMs drop down to the high 500s, but they recover without a problem. That said, I did manage to stall twice today, the first time I stalled since I did these changes.
Of course I wasn't logging when the first stall happened. I hit the gas from a standstill, then slammed on the brake when I realized that I couldn't make it through the intersection. It started up easily enough. The second stall I was logging, and happened when I was about to try to reproduce the stall.
I noticed the IAC was open at around 30 steps at idle, so I gave the screw a quarter turn to bring it down to 15-20 steps a minute or two after the stall. I'm hoping that by not allowing it to close completely that I can keep it from stalling, which I think is what FABombjoy was suggesting. However, I've noticed that after enough driving, the IAC will read 0 steps but the idle will be around 1000 RPM. I believe that MS thinks the the IAC is closed, but it's actually not closed. If I turn the car off and on again, the idle goes back to 790 RPM and the IAC goes back to around 15 steps.
Now, I know that it's calibrating to completely closed on startup. It just seems to be losing the calibration the longer the car is on. I tried increasing the minimum steps from 1 to 2, in case that had anything to do with it. I'd like to close the IAC more, but I need it to behave more reliably before I do that to keep the idle down.
Anyone else have this problem?
The log has three marks at the point where it stalled (around time 5421 is the stall). Near the end of the log you can see a high idle while the IAC is closed. I then turn the car off and on again and the idle goes back to normal and the IAC is a bit open:
2019-09-10_07.38.21.msl.zip
Tune:
CurrentTune.msq
Thanks!
-- Joe