Fuel trim difference between bank 1 & 2
 

Just starting the remote tuning process after swapping in 1000cc injectors on my car. Currently have the base map from Eugene loaded in the car. I’m noticing that the fuel trims between bank 1 and 2 are different.

Bank 1 reads normal at about 96-97% STFT, 100% LTFT.

Bank 2 reads ~106-108% STFT, 90% LTFT.

I was originally thinking that the trim for bank 2 is 10% higher from looking at the short term, but if you consider that the long term is 10% less, the banks are nearly identical. Weird

Is this something to be concerned about? Will the Bank 2 LTFT eventually go back to ~100% and then the banks will be equal in fuel trim?

I already looked for leaks (cigar-smoke tested intake.. nothing. Hose-to-ear tested intake manifold area.. nothing. No audible exhaust leaks)


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May have answered my own question. Reset ECU to clear stored fuel trims and everything appears to be the same between banks during idle. I’ll see if they change during a driving session


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Curious as to where you found what the normal parameter should be? Thanks

100% +/- 5% is a good range for short term fuel trims to fall in, according to Eugene.

To get both banks to be in this range, I reset the ECU through the ECUTEK ProECU app. I had the battery unplugged in the past so I’m not sure why that didn’t reset the ECU to clear previously stored trims? Maybe the ECUTEK reset procedure clears additional parameters compared to a battery-disconnect reset


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Good info. thanks. I'm always looking for datalogging parameters. Haven't found much around.