Clarifacation on Fuel Trim %'s,what does it mean?

[SIERRA]

O.K. it is said that you want optimal trims set at 0-2%,but no where have I read what this means ! So when I set up my truck injector slope at - 7% to give me a long term of 0.78-0.00% at cruising speed of 110kms.and approx.1950 rpms.Now when I went to -10%, I got 1.78 and 2.34% then I went extreme and set slope at +5% and got 13.28%, so in the threads it says if you increase slope size your injector size "DECREASES"giving a leaner amount of fuel.Then why are the numbers higher in % ? Can someone explain this ? To me its telling me that as I increase injector slope I am richining the system.

[Ill_Born_SS]

You may have to go into the VIEW tab of DataViewer, go to Parameter Modifiers, go to E40 Equivalence Ratio Invert and either select it or unselect it. The opposite of what is now selected.
Not sure if this pertains to your application, as you offer no other information. (Predator #,revision,vehicle,engine)

[06MonteSS]

nope, no need to do that for the trucks... no need to invert...

he's talking about his fuel trim numbers anyway, not the AFR... his fuel trims were at 13%...

Sierra... set everything back to default settings... put on about 50 miles... do a new steady driving/cruising data log, and post it up here, and I'll take a look at it..

[jwdemon]

Come on Lew, he just wants to understand what he's doing.

Sierra, when you adjust your injector slope, you're not actually enriching or leaning out the system because the computer is always going to compensate to keep the correct AFR. The fuel trim values are showing you how far the computer is compensating, so the farther away you set your injector slope the more your computer compensates, showing you that trim value. It's kinda like the adage "Time is money!", the more the computer has to compensate the more it's gonna cost you. Setting your injector slope to get the fuel trims as close to 0 as possible makes the computer work faster and more efficiently.

Fuel trims @ 0 = 0 Computer Compensation
0 Computer Compensation = Faster, More Efficient Response

[SIERRA]

Hello guys been away, o.k. Monte ss my trims were not that high (+13%) they were there when I upped the slope to +5%,fooling around with numbers ! So I found the trucks sweet spot at -6 to -7 % on the slope which gave me a reading of 0.00% to 0.78% on both banks.It's good to know that this has nothing to do with rich/lean but I sure noticed that when you do change the trim percents the tone of the motor changes and so does the throttle response!So for example if the trims were set to + 10 larger injectors and left there what is the consiquences?

[2sscamaro]

Come on Lew, he just wants to understand what he's doing.

Sierra, when you adjust your injector slope, you're not actually enriching or leaning out the system because the computer is always going to compensate to keep the correct AFR. The fuel trim values are showing you how far the computer is compensating, so the farther away you set your injector slope the more your computer compensates, showing you that trim value. It's kinda like the adage "Time is money!", the more the computer has to compensate the more it's gonna cost you. Setting your injector slope to get the fuel trims as close to 0 as possible makes the computer work faster and more efficiently.

Fuel trims @ 0 = 0 Computer Compensation
0 Computer Compensation = Faster, More Efficient Response

Sooooo based on this premise I could set my LTFT's at say -20 and my engine would not be running a rich mixture, but the ECM would have to work harder at maintaining stoich?