ECU only hits AFR target while running autotune
 

I've been playing with my MS2 PNP in my 2000 for a few days now. I can get the car running pretty well, roughly hitting its AFR targets while running autotune. After I hit apply and save on ecu, then start driving around again, the AFRs go super lean, no where near their targets. I feel like there is something simple im doing wrong, but I can't figure out what.

I usually turn off AFR/EGO Control when I'm autotuning. I know folks say autotuning still works with EGO on, but I have better luck with it off.

Do you have MegaLogViewer?

What exactly does AFR/EGO control do? I believe I have mega log viewer. I haven't been logging since, in my opinion, I haven't had anything to log. My plan was to use autotune to get the VE table in roughly the right place ant then log. The last two times I thought I was there, I went to try the new VE table map and it was waaayyy off.

We can't do much without seeing your tune and logs of exactly what you're seeing.

VEAL takes EGO into account, there is no need to disable it. If EGO has 15% authority it can add 15% more fuel or pull 15% fuel from your set VE in the table on the fly, while making no permanent corrections on the table. I use it to account for air temperature changes as my MAT air density table is zero'd out, still tuning my VE table.

I think the MAT air density table in MS2 functions differently than MS3, but it may be worth setting MAT corrections to 100% across the board as those will throw everything off when tuning your VE.

I'll do my best to take some in the next few days. Im just uneasy running the car at 16-17 AFR when cruising. Seems pretty lean to me.

I'll take a look at the MAT air density table. Thanks!

Make sure that you have AutoTune configured to actually save changes and apply/push them to the microcontroller.

If you have autotune running but aren't live updating (can't remember the name of the checkbox because I haven't had the laptop out in a while), it will continually adjust the VE trying to correct (i.e if you are Lean it will continue to adjust the VE to be richer) until you eventually apply the VE Table and then it is way off.

It's pretty tough to damage anything in low load cruise cells. A lot of us target 16.0 in those cells.

I have the update controller box checked, if thats what you are referring to.

Thats good to hear. I feel a bit better about taking logs then. I'll try to do so things weekend.

I went out and ran autotune again this weekend and then took a datalog (I'll post later if need be). Everything went surprisingly well... until I went to tune idle. I selected some of my idle cells and adjusted them and used the interpolate buttons and everything was out of whack again after that. Do the interpolate buttons modify the whole table instead of just the cells you select?

You should always keep backup files of your tunes, therefore you should be able compare the fuel table before and after you tried interpolating idle. But it'll just interpolate what's selected, not the whole table. Interpolate takes the 4 corners of the selected cells and linearly interpolates everything inbetween. Idle requirements don't seem to be too linear, so I would tune each cell individually. This should be done by hand and not with auto tune.

There should already be backups of your tune. Tunerstudio does it automatically. (though you may not know what tune file was due to what change)