OK, sorry if this is a very basic, or dumb, question. Working hard to further my learning curve on TunerPro and tuning in general. So, can someone explain what the numbers, in the cells of this table, or any table for that matter, represent? Are they the result of a function? If so, what is used to get that number? When making changes to your tune, is this a table you would adjust?
Thanks
when the car is cold, before the oxygen sensor start working, this table is used to determine the air/fuel ratio. the numbers in the cells are the parts of air per part of fuel.
14.7:1 is ideal for normal gasoline, and a cold engine needs more fuel, hence the richer mixture as temperature goes down.
it's set a bit rich for safety.
would i adjust it? no, probably not.
if your maf table (or ve table, if you have no maf) is set up properly, the factory values are fine, and on a car with functional oxygen sensors, the table is only used for the first minute or two before the car warms up.
i did notice the description of that table in my XDF is both wrong and undescriptive, so im going to fix that.
have i told you to press F10 in tunerpro, so you have the item descriptions up while you're going through parameters?
Steve, thanks for the explaination. So those numbers are actual, re: that 1st cell number (8.0) is 8.0/1 AFR, less units of air per fuel unit making that a rich mixture?Originally Posted by steveo
yeah, they are, but they're afr TARGETS. thats an important thing to understand while tuning this stuff. how accurate those numbers end up being in the real world depends on how accurate the rest of your calibration are; maf table, injector constant, etc.
as soon as closed loop is entered this table is ignored
Last edited by steveo; 10-13-2014 at 07:21 PM.
GOT IT!! THANKS
no problemo.
this kind of conversation reminds me of things i have to document a bit better in my xdf.
my goal is that a new-ish tuner can read that description that pops up with the f10 key (or hovering the mouse over an item in the list) and get a decent understanding of how it works, and how to tune it.
i've spent way more time than i'd like to admit on that already, but there's so much more to do
Good info. Steveo, which xdf is yours?
EDIT-- I see it in your sig. :)
I can tell you, as a bonafide NUBE, your documentation is much appreciated! However, because I was so new to it, most of the explanations were "over my head" as they referenced other tables, flags and terminology that was foreign to me. Now that I've spent some time reading, which at first was like researching how to perform orbitozygomatic craniotomy surgery, in other words I had very little point of reference, I can better understand, and relate, what the documentation is saying. I know what a daunting task documentation can be.
Several years ago I developed an application documenting the proper use and safety precautions of hazardous materials in a large vehicle repair facility. I used MS Access, and since one of the primary uses was first aid procedures, a line mechanic, on the floor, had to be able to quickly find the info he needed. By far, the most time consuming, PITA operation was content/item specific help dialogue. So, again, I say thank you Steve.
One more thing. In the post above you said;
how are those numbers different than say one you put into *Idle Speed RPM. table?
other than the fact that they're RPM?
the idle speed RPM table runs in a closed control loop. it measures, makes a change, and re-measures. unless you run out of IAC travel, it's going to get close to that idle speed.
the open loop AFR is just calculated and that's it. it has no way of knowing if the calculation is accurate since it's open loop. so unless you measure yourself (with a wideband) or unless you're sure all the other parts of that calculation are perfect (MAF, VE, injector constant) you'll never know if the values you put in that table are being achieved or not.
OK--I see.
The PCM might save the learned fuel corrections from it's closed loop operation and apply them on the next open loop start which could make the calculation more accurate.
true, this particular ecm doesn't use the ordinary BLM trims that are stored until at least 60c of coolant temperature by default; and only cells that are trimmed above 128 persist.
This image reminds me of how much I hate things in TunerPro being upside down and just plain backwards now! The table is inverted from the way I like to look at it. That is colder temps at the bottem and warmer on the top.
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