With a good idle of 750 - 800 the IAC step was 92, then the IACstep changed to 94 which dropped the idle to 600-750. Then timing fell from 17 to 15 and the idle fell to the 500s, 400s, then stalled IACstep was constant at 94 during this.

look at idle PWM%

i don't see how the timing dropping 2° would cause the engine to die, the idle valve should have opened when the speed dropped. what were the AFRs?


post the log.

File is 3.5Mb too large to upload. Anyway to shrink it down?

open it in excel and delete out some of the rows of data that aren't important.

then save a new file and attach that.

Start at ~625s

Wow, I feel stupid. I should have deleted the rows based on time instead of data columns

yes, because i think im missing some data I wanted to see :)

You need to work on the AFRs in your idle area, that's why it oscillates when coming down to idle...

when it stalled it was constantly getting richer and the valve seemed to be in a more closed position as compared to the rest of the map and it was very nonreactive to try to stop it from stalling. the fact that it was so rich and getting richer didnt help.

Try this one

that one is brokenz. :)


it just looks like something happened when you came back to idle and the valve had no real reaction to the engine speed...might want more I value.

you need to lean it up at idle and smooth it out to help stabilize as well.

Even a 10* drop in timing won't stall your engine. I haven't opened the log; TunerStudio sucks in opening other people's logs.

I'll smooth the idle. After looking at my ve table I noticed that I didn't smooth my idle cells after auto tuning.

It's doing this consistently now. I have made some adjustments to my closed loop settings. I adjusted my PID lockout settings because sometimes it will stall when I put the clutch in coming to a stop from high speed.

wait tunerstudio can open logs?

Not exactly. It just opens the log with megalog viewer. It just has a tab to do this in tunerstudio.

datalogging --> view with megalogviewer

watch your idle pwm% when you drive and hit the clutch and see if it's reacting like you want. this is why i lowered my upper RPM, if I'd cruise below it in the 1500RPM zone, the PID work kick in and try to close the valve while the car was still moving, then when i finally hit the clutch the thing would almost stall and kinda act like your issue.

compress as zip, then attach. that should save a ton of space for a file like that.

My rpm values are 800 and 1300. Lowering the lower limit didn't seem to change much. Moving the upper limit seems to change quite a bit. It seems like these values should encompass your idle range. I would need to set mine to 700 - 1050, but it doesn't seem to like that as much.

When logging, is PWM% listed liek this, or is it listed in a different way? I don't see anything listed as PWM%

I have PWM idle duty, is that the same thing?

yeah that.

maybe that's not the issue then. dunno.

I am taking a stab at tuning the idle with a/c. However I am not using closed loop idle. My idle without the a/c is stable. However when I turn on the a/c, the idle drops about 400 rpms and then osicalates about that much too. If Im lucky it won't stall out, but about 99.9% of the time it does.


After adjusting fuel in my idle cells while the a/c is on, the afrs were much steadier bouncing between 14-15.7, but still a low rpm of 500+-. I am not too sure where to go to in tunerstudio to adjust the IAC valve. The only thing I can think of is to turn the screw and raise it. The idle advance seems to keep the idle steady, but as stated before the rpms are too low.

you gotta use closed loop. why wouldnt you, especially with a/c?