At Wit's End! Help! (Fuel Trims)

[Sharkbit79]

Hello everyone, I have been a lurker for a few years, and recently started tuning my H/C Z06. I am running fast injectors and i have the correct data. (AFAIK). My problem is tuning with fuel trims or using WB. I think the tune is set up correctly but it seems everytime I paste the trim error into the VE table, the trims go crazy. They will either go extremely lean or rich. I cant seem to get right around the -5 to 0% mark without overshooting.

I have read all the information I could find about tuning the fuel trims, but I just feel like I am missing something. The car idles ok, and drives ok, but it just seems the fueling is all over the place. I have my NGK wideband setup to log AFR error and it seems somewhat more consistent than the STFT, but I still cant seem to get the trims dialed in. I have attached my tune, please look at it and see if I am missing something.

Thanks in advance.

Mods
Trick flow 215 heads
TSP 228r
1 7/8 headers, gutted xpipe
stock intake
Fast 42lb injectors (I used the siemens data, because of the matching part number)
Working Tune.hptAFR Error Config.cfg

[blown 04]

are you tuning trying to tune with the wideband in closed loop? If you want to use trims for tuning try using your Ltft, they will settle your STFT down. Get the LTFT close then turn them off if you like. If you use your wideband to tune do it in openloop.

[Sharkbit79]

I am currently in open loop with fuel trims disabled so that I can use wideband. I may try to use LTFT + STFT and see what happens. It just seems like its incredibly hard to dial the VE in compared to most experiences I read on here.

[Kyne]

Have you tried paste special> multiply by % -1/2?

[sarg]

I found just using stft with a large sample to do pretty well when in closed loop. In a little over an hour I was able to get everything to settle in +- 2% with ltft turned back on. I would also mult by 1/2 each change. Worth a shot!

[Sharkbit79]

Well I got frustrated with the WB tuning so I decided to turn the STFT + LTFT. Trims settled out nicely, with only a few spikes here and there. I think its from messing with the VE table so much. The changes > Multiply by % - half, accepted well, and seems like I am making progress again. Hopefully I can get it sorted pretty quick and get on to MAF tuning.

Thanks for the replies, and any more help you can provide is appreciated.

[sarg]

Rather than trying to add the two, I would disable LTFT and just go off short term. Just make sure to get a bunch of counts in steady state (cruising and such with no rapid throttle movements) and it will weed out the transient stuff on its own.