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Discussion Starter · #1 ·
Hello all!

Currently having some issues with my '09 GT-R. A steering wheel was installed, because of this the battery was disconnected. After this, a heavier acceleration has been done from 1st gear with wheel spins. After this, the car started to cut the power at around 4000rpm. Took it to the tuner (I'm on Ecutek) and he said that my short term fuel trim on bank#1 is too high and it cuts fuel when it reaches 115%, so the problem was the high difference between the two sides.
Decided to change spark plugs, that did not help. Next step was the O2 sensor on the bank#1 side. That didn't help too :( My next thought was to disconnect the battery again. At the first start up, I cannot change the map, and on the ecutek app, I didn't see some values, they were stuck on the default value. At the second start, ecutek worked fine, map switching was possible, and both short term fuel trims and AFR values were went back to the correct values. At this point I thought it worked, but not.... After a few kms the short term fuel trims started to make some difference, and the same behavior have been reached later, so bank#1 has higher short term fuel trim, and the Ecutek shuts the fuel down.

As I have read that sometimes battery change/disconnect can make Ecutek crazy, decided to ask for a newer tune. A new tune with new Ecutek have been flashed onto the car, everything looked fine. After the tune, several hard pulls have been done, the short term fuel trims have showed a growing difference again, but much smaller and this time the bank#2 had the higher fuel trim....weird.

The weirdest is just coming, because I have had a similar hard acceleration from first gear, which was done before the first fuel cut. This time the short term fuel trims have switched to 100-100, which is fix like hell. On idle it is 100-100 too, on lower rpm's, the stft starts moving a bit, but then it switches again to 100-100.

I'm getting confused, about the root cause. Can anybody help me what the hell could go on with my car?
Mods which has influence on the engine: Ecutek, GFB Hybrid BOV, catless dp, catless titanium y pipe, 90mm titanium exhaust
Finally, I have logs from both conditions:
When the bank#1 had high stft, with fuel cut:
After new tune, with a bit different stft:
After the stft switched to fix 100:

Any help would be appreciated!! To be honest, I don't know where to go next

4,577 Posts
Your probably best dealing with a tuner nearer home,there may also be a couple of Germans on here who could point you in the right direction. I think black supra is German (apologies if incorrect)
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