Target based fuel maps, Short term fuel trims

I’m having trouble getting started with tuning my n54. I’m reflash tuning and using tunerpro to modify the maps with a well known definition file.

My trouble is that maybe i’m just not understanding, but I have switched LTFT’s off, there’s no way for me to disable STFT that I can find, and my fuel maps are purely target based. I’m a bit confused at just altering the maps, am i supposed to go through and define what I’d like the afr to be at every point in the map, and just let the short term trims work to achieve that? That seems wrong to me as it’d cause my short term trims to be very high, I’ve uploaded an image of the maps.

The other approach I’m guessing would be to choose the cell I need to make an adjustment in, multiply by the percentage shown by the short term trim to get the true value, and then alter the afr in that cell by, calculating the correction and then apply that correction to the afr target in the map? I’m just a bit confused, I’ve spent months taking these courses and learning as much as I can, felt confident but now this all seems so unfamiliar to me now that i’m actually doing it.

fuel map is in the attachment.

You need to understand how your ECU operates. Your ECU calculates the required fuel pulse width based on your targets -- target richer, and it should be richer.

If the fuel table is just targets, and changing the targets does not result in hitting that target, without additional short term fuel trims, then the calculation of the air mass is incorrect (so a MAF calibration or similar is required), or the injector data is not correct. Of course all sensors like fuel pressure, air temp could also have an affect. Otherwise the ECU could "do the math" and hit those targets.

What are your current STFT? if it's only a few percent -- then it's basically hitting the target, if it's 10% then something is wrong.

The challenge with factory ECU is we often don't understand all of their tables -- and you could be changing a table that's not even being used. So a good first test is to change an area of the table quite a lot (say make it 5% richer in one RPM/Load area) to make sure that table is active. Log that, now you can put it back and move on to what you wanted to change knowing that you are editing the correct table.