what controls ETC idle airflow when rolling ?

[07GTS]

i have an issue where idle is fine but as soon as it gets a speed signal above adaptive idle it revs to 1000rpm and spark is being removed to try lower it (not thru adaptive control) but the TPS locks at a minimum 9.8% where idle is normally around 5-6% and it also holds revs durin gear changes which is annoying and it also affects deceleration

manual trans, ive tried lowering min airflow, idle speed min, idle followers, airflow step down, raising area scalar, lower percent max to 0
only mod i done that i think caused it is the stock TB has been ported to take the lumps out, i have current tune file below and log


top pic is idle rolling with no TPS pedal but TB still opens dark green is pedal light green is TB


this pic is gear change TB drops lower but then increases for some reason holding rpm and affecting decel

[gmtech16450yz]

It looks to me like your min air is too low and your ECT multiplier is too high. I'm saying min air is too low because you went down to ~3% after that throttle blip in your log, that's a clue. So what happens is at idle and not moving, your adaptive idle is trying to compensate for the low min air. Once you start moving, the ECT multiplier comes into play, and at the same time you're losing adaptive control. If the ECT is too high, it will cause the high idle you're seeing.

I'm not 100% sure though because you're missing some important PIDs for idle tuning. Try these layout/channel/chart files I've attached, they will tell you EXACTLY what's happening with your idle. When you log with these configs, take a look at the bottom row of PID's, they're all set up to read the same as far as Lb/Hour, including the maf itself. That way you can SEE what your min air is set at in relation to what it's desiring for airflow. These scanner readouts will make idle tuning WAY easier. Oh and btw you'll probably want to dial in some amount of ramp in your min air table. You most likely would want the throttle to not go down to the same value on decel at 1000rpm as you would at 5000rpm.

Any of that make sense? lol.

Log with these...

gmtech idle tuning channels.Channels.xml

gmtech idle tuning charts.Charts.xml

gmtech Idle tuning layout.Layout.xml

(Open your scanner software first, then open these by clicking on "Layout", "Open Channel File" and "Charts Setup" menus.)

Your scanner should look like this in the bottom row if you get the files opened and running...

Idle tuning layout.JPG

[07GTS]

yea thanks it makes sense ill give them a go but im not sure if i have them available in my channels list, just tried adding them but they dont get a blue arrow so i assume thats not good..? should i connect to vehicle or offline should add them still, yea my min air usually have it ramp up as rpm increase but just left it low so when i figured out the gear change rpm hang it would drop lower and id notice it, ok so the ECT multiplier isnt a constant based on temps it comes into play and out with adaptive enable as well..?

[Area47]

best thing to get your bases covered is watch the timing at idle. if it is under the target, you have too much raf. if it is over the target, you raf is too low. same with in gear and coasting. . it won;t get your coasting perfect, but gives you an avenue to attack first.

[07GTS]

yea hopefully i get it under control now that i know that multiplier table does something more then what it says that will help, then ill get the stationary idle dialed in and it should all finally work together, ill have a go this weekend see how it pans out, thanks for the info

[NJ_Phil]

FWIW I always have the "Idle Adapt Advance" channel open and in the graph and know everything is good if it never adapts more than +-1 degree of spark.
Anything more than that tells me some other setting is out of whack. I know this is an oversimplified way to look at it, but has been working well so far

[07GTS]

It looks to me like your min air is too low and your ECT multiplier is too high. I'm saying min air is too low because you went down to ~3% after that throttle blip in your log, that's a clue. So what happens is at idle and not moving, your adaptive idle is trying to compensate for the low min air. Once you start moving, the ECT multiplier comes into play, and at the same time you're losing adaptive control. If the ECT is too high, it will cause the high idle you're seeing.

finally had some time to do some more adjusting (damn winter weather) and u were bang on with the min air and ECT multiplier i had to take about 74% out of the multiplier and just find the sweet spot where it helps but dosnt affect idle, then min air increased a little and still might need a little more but its smoothed idle out and i think this should all help with cold starts also and gear shifting / decel is back to normal

[gmtech16450yz]

finally had some time to do some more adjusting (damn winter weather) and u were bang on with the min air and ECT multiplier i had to take about 74% out of the multiplier and just find the sweet spot where it helps but dosnt affect idle, then min air increased a little and still might need a little more but its smoothed idle out and i think this should all help with cold starts also and gear shifting / decel is back to normal

Yay! It's pretty cool to be able to help someone on the other side of the world. Glad it helped.

[07GTS]

thought i has this fixed but its still an issue turned out that the min air was too low and even a tap of the pedal would cause the idle to dip into a stall, now even with the min air set to all zero the idle is fine but soon as it sees speedo over adaptive 2kph it revs up to 2000rpm 13% tps so something somewhere is telling it to, i just dont get how rolling idle is any different to stationary idle as to why rolling idle increases rpm when there is no extra load on engine and min air is all zeroed (stationary idle can be setup perfect with only 1-2 deg spark correction either way but once rolling it just revs up) could it be that there is a set rolling idle % position above idle and now since i have taken the lumps out of the stock throttle body what was before a small increase is now more airflow and it dosnt know any different..? its defiantly an airflow thing spark can only help but not fix it, even if i get adaptive idle to pull enough air out thru error it always goes back to zero error and thus lets it back up and it still goes back to 2000rpm then it pulls it down again causing a serge so that tells me something to do with airflow is holding it up but i cant see what, ill attach current tune and a log of it happening in that log the min air is zeroed out and u can see pedal is never pressed

[07GTS]

starting to think i might have to make up another throttle blade with just a smidge more on the sides just so it seals a little more in the 0-20% areas see if that helps