Fuel trims and temperature question

[MrBigglesworth]

Quick question for those that log this kind of data on a 2.0T

- How much do your long term fuel trims change with temperature?

I understand that lower temps means higher air density so should push values a bit more positive as the O2 sensor adjusts for the mixture, but I am quite interested in actual (Vag COM block 32 or just with a bluetooth device) values.

I find that my idle/add trim doesn't move much, but my mult/part/throttle value moves by around 4% between say an outside temp of 0 degrees and an outside temp 20 degrees Celsius. Wondering what other people get?

[MrBigglesworth]

Anyone got any data to share? If not, maybe a few of you could note the fuel trims now and then note it when the temp changes and let me know.

Cheers

[derrek]

They shouldn't change a lot with temp but should change with driving style and fuel quality


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[MrBigglesworth]

Mine swings quite a bit - even with same tank of fuel let alone the same make (we've had one day to another swings of 12-13 degrees) and this makes up to a 2% difference in fuel trim... Wonder what could cause that?