Hondata

Had been dyno tuning a H22A S300 Turbo for a few hours, and it was going very well. Tuned upto 6psi and drivability was fine on the dyno.
Then turned off the car (had done so a few times for a few breaks during the dyno tuning, smae as usual) started it up and all of a sudden all the tune was running lean, idle was going to to 17 AFR, and rest of the tune was lean too?
Added about 10 points to the total fuel trim and it went back to about 14, then started leaning more, then went back a bit, started it up a couple of hours later was running fine, then started running lean again, drove for about 10 minutes of +5 fuel trim, then idled it and it started leaning out so had to up the fuel trim to +10 again.
We were gonig to tune it upto 1 bar that day but gave up until we could figure out whats up with the fuel leaning out, seems to change on an hour to hour basis, sometimes put the fuel trim back to 0 and it drives fine again.
Checked the fuel compensation for water and air, both at 0 (when it gets to the running temps, all the stock s300 settings..) fuel pressure is fine, map sensor seems fine (3bar GM)
All airtemps and water temps seems fine, not getting anything different from first few hours of dynoing, then just went wacky..
Any quick fix ideas to check? Before i get a few datalogs of it going well and badly..

What type of oxygen sensor are you using. Is the car in open or closed loop? how is it all hooked up?

datalogs and calibrations need to be posted as well

was running in open loop as only has the stock o2 sensor in place, was being tuned with a motec o2 sensor in a second bung in the exhaust (not hooked into smanger or anything for auto tuning...)
Everything was fine for a few hours of tuning, and had had been driving fine on a old tune for a few days, just took to the dyno to optimize the below boost drivability a bit more and to tune for a bit more boost.

But later that night at a set of lights... the pressure plate on the clutch decided to go and break! so its off the road until i get the new clutch kit installed, dont things just have perfect timing for breakage...

Its a funny thing, just turned it off for a few mins on the dyno and then it started leaning out at idle and everywhere, the only thing I can see that would affect leaning would be the intake air temp, but it nowhere near reached those sort of temps to need to lean the mixture...
Mecahnic things it could be the map sensor (GM) but it looks likes its fine when its moving around the fuel/ignition tables, right areas an all...

Oh one thing, it reads the right vacume/boost areas on the tables, but when you look at the number on the actual map sensor reading it seems WAY off, like reading 20psi or something when its not even on boost, but its at the correct point in the tables its reading? (has always done this even before the leaning out problem)

Heres the tune file and a datalog the was done before it started leaning out the whole map.
I notice when i scroll through the datalog, when its reading around the 0.03 to 0.29 mbar range in the fuel/ign tables, its saying 15psi+ on the sensors screen for map??

Go to Options, Settings and change your units and base units.

Your 12 second datalog does not show anything.

Do a leak down test on the car. I have seen the same thing happen with bad rings before.

Jason