Compensate for long term & short term fuel trim

petah · Post by **petah** » Tue Mar 14, 2006 6:55 pm

Hondata,

I understand that short term fuel trim will avg out to long term fuel trim.

What I don't understand is: in the hondata technical video it showed -3% for long term fuel trim. 4% fuel was added in the video.

I thought -3% fuel trim means ECU is subtracting 3% of fuel over time and the video should show trimming of 4% fuel instead of adding 4% of fuel to the partial throttle in the video? (won't adding 4% of fuel make the fuel trim off even more?)

This is the video i am talking about: http://hondata.net/media/kprotraining/fueltrim.mov

Any inputs?

Thanks.

portandpolish · Post by **portandpolish** » Wed Mar 15, 2006 1:51 am

Yeah that kinda confused me abit too.

petah · Post by **petah** » Wed Mar 15, 2006 2:17 pm

bump for some input

Post by **Spunkster** » Wed Mar 15, 2006 2:49 pm

Yes Doug appears to have made a mistake. If the fuel trim is negative you must subtract fuel. Sorry for the confusion.

petah · Post by **petah** » Wed Mar 15, 2006 4:11 pm

thanks! Still a newbie at this and don't want other people watching the video and go out and make more wrong adjustments!

By the way these videos are great and guiding me along the sharp learning curve. Thanks again!

Bflaker · Post by **Bflaker** » Wed Mar 12, 2008 11:03 am

So, don't you think you should change the vid? I tuned my car thinking he was right, and my LTFT kept getting worse and worse. Finally I did some research on clubrsx.com and found out that it was a mistake in the vid. That suxors :oops: