Idle Airflow Monitoring/Histogram w/no MAF

[mm_n_p]

I'm sure that I am overlooking the obvious but I just cant seem to process how to monitor base idle airflow w/out a MAF. Is this possible?

Hell, I may be going in the wrong direction completely because I honestly didn't think that this table (Idle Airflow) would be accessed running speed density but I found myself having a hanging idle issue after cleaning the throttle body and as a last resort I lowered that table by 75% and it was very effective.

Any input is greatly appreciated.

Oh, this is on a 2006 GTO.

[07GTS]

"dynamic airflow" is a good one to monitor

[mm_n_p]

Well crap, then I don't understand what I did when I cleaned my TB. I assumed Dynamic Airflow at first but when I monitored my "Base Running Airflow" over the weekend after I started having runaway and hanging idle issues the values were nearly double over what the car had been tuned at previously which I did with an active MAF and had a nice well mannered idle. When I noticed this I just assumed that couldn't be right and kept looking.
I guess I will revisit idle tuning which is annoying for a simple Throttle Body cleaning I just don't understand how it can be so far off now. Hopefully I can remember everything again, this is my first gen4 idle tune w/cam which is different than the gen3's and a large learning curve (for my old ass anyway).

Thank you O7GTS for the quick response.

[07GTS]

there is a TB relearn feature for when u clean it in the scanner could give that a go, if its only changed since a clean then put the settings back and try the relearn

[mm_n_p]

there is a TB relearn feature for when u clean it in the scanner could give that a go, if its only changed since a clean then put the settings back and try the relearn

Was first thing I tried and was patient for a full day while the idle raced past 2k rpms on several ocassions but hoping I was just having an abnormally bad episode of TB relearn. During that time, I never noticed any discernible improvement after at least 20 key cycles, couple hundred miles of driving and about 30 min of idle time with AC on and off. Was an aggrevating day...

After that I finally gave up and dropped my "Idle Airflow Min" (or RAF) down by nearly 50% to get a decent idle back that wasn't trying to pull 10* of timing out. By doing this, my idle is rock solid again when sitting still but i have a hanging idle when rolling/moving which I never had before. Currently my Idle Air Table is about 60% of stock which I know isnt right and when I monitor my Idle AirFlow lb/min I have really high values, upwards of 80-90 lb/min at 800rpm which doesn't make any sense to me.

Something is amiss and simply cleaning the TB shouldn't cause a change in the tune that drastically. I'm wondering if I may have damaged the TB somehow... I need to find a way to rule that out I guess before I commence to attempting a re-tune on the idle, which I'm not convinced will even work at this point.

-Steve

[07GTS]

yea sounds like something is going on if u have lowered min air but 50% to fix it, sure there isnt any air leaks anywhere ? also what is your idle TPS % now is it same as its been or lower now ? if its physically lower % then its prob an air leak, i have ported my own TB and stuffed around with it and it hasnt been affected by it so they are pretty tuff just dont force it past it limits or when powered up

[mm_n_p]

I did consider a leak since its certainly the symptoms. I haven?t smoke tested it but I did pull the TB back off and change the gasket out. I guess I could have damaged the second gasket as well but the odds have certainly diminished and these gaskets are pretty forgiving. I will try the old spray cleaner leak test this afternoon since I will actually have a minute to devote to this.

As far as damaging it... I pulled TB off to clean and manhandled it as if it was the old cable style but they feel robust and didn't even consider the thought of damaging it at the time but sounds like it may be a possibility. I will pull up some old logs and compare idle range %. If memory serves me correctly, I?m somewhere around 10-12% now which seams normal but that doesn?t necessarily mean the blade angle is in that range physically does it, which if that?s the case it could be where my vacuum leak is I guess.

Maybe tonight I can have a better understanding of what?s going on.

Thanks again for the help.

[07GTS]

yes i always log throttle pedal and throttle body then u can see where the throttle body sits if u need a comparison cos the pedal could change depending on condition, just for an example my first throttle body i made up a new blade for it and trimmed it back so u can barely see any light thru it and it was still too much air for idle (idled at like 1% warm) so it can be a very small increase in air to cause a higher idle

[mm_n_p]

I?m unable to tune it out... I went as far as zeroing out the RAF table just to see how it acted and was still not able to bring idle down below 800rpms, and on top of that it was pulling 9* of timing just to hold 800.

I also noticed my VE had leaned out roughly 12-15% In idle area and just for grins made the necessary adjustments to see if it would help. May have helped it run a tad smoother but nothing drastic.

at this point I?m almost certain that it?s mechanical so I pull intake, put laptop under hood and manually move butterfly with keyboard while looking for anything that throws a flag...

Is this normal? https://youtu.be/HZUbTepmLd0

It seems to have a catch at the 20% mark, you can hear it as it crossed that threshold...

[07GTS]

couldn't see much im only on phone tho but the testing to change percentage isn't always smooth mine sometimes stops or flicks back, but looking at your zero point is that a gap at the bottom ? i have a feeling something happens to these but we can't access the tables to correct it mine done a similar thing after porting but i got a new TB and was still the same, i can sit at idle fine but soon as i roll it will increase rpm soon as its above adaptive idle control, im still working on a fix but getting closer, try increasing the ETC scaler that should lower idle percentage but then u might have to increase min airflow but i think what this does is the rolling idle has a percentage where idle has min airflow so its lowering the rolling percentage thru etc size but redoing min air, go up in ETC scaler steps of 500 see how it goes im still testing on mine

[mm_n_p]

Update -
Although I'm not sure if that "catch" in my throttle body blade travel around 20% is normal I did get an opportunity to try another TB and all is well again... daisy's, unicorns and gumdrop forest good! .

A came across a very clean factory GM, LS3 TB (Gold Blade) and although hesitant to even try it since the rotation is opposite direction, I really didn't have anything to lose. With that being said, I put it on and it was like heaven had descended up my my idle and consumed its demons.

Every time I picked up my laptop to start a re-tune process on a vehicle that ran perfect before a seemingly simple TB cleaning, made my skin crawl. I was bound and determined to prove/disprove the mechanical side first and after a little monitoring of idle and realizing that it was just waaaaay to far off i started calling everybody I knew for an LS2 throttle body - which is like finding a yeti these days. Luckily i stumbled across this used LS3 TB... I may be $50 poorer but so relieved. LOL

I wish I know what the exact issue was with the old TB, but i'm sure as hell not going to spend any more time on it to find out. Everything pointed to vacuum leak but I didn't have one, externally anyway, so it must have been getting around the throttle plate and just unable to do anything about it, either by just being worn out in the blade seating area which didnt seam to show any signs of, maybe it was loosing its TPS reference or I guess it could have possibly been in my tune but I just couldn't swallow that theory with how well it previously ran.

None the less... I'm chalking this up as win with a lesson learned on cleaning ETC TB's. - Either I damaged it by opening the blade by hand with it off the car and/or my TB cleaner got into the electronics somehow, from now on, I will use HPtuners, or my foot feed to open the blade AND apply my cleaner to a rag before cleaning, no direct spray, just to be safe.

I will go through a idle re-tune procedure now just to see if the reverse travel blade on the LS3 TB makes any significant difference to the tune, then I'll button it all back up and drive it like I stole it.

Thank you very much for your help
-Steve

[07GTS]

is a strange one good that its now fixed (i had to find another LS2 TB wasnt cheap), just thinking if u have sprayed into it then if it was a proper TB cleaner they can be very harsh on oils and may have damaged a seal, cos i have had mine off many times and cleaned and moved blade alot but i only use a rag never a cleaner

[mm_n_p]

Now that you say that, some of the grime was a little stubborn for the Throttle Body Cleaner so I reached over and grabbed a can of Brake Cleaner for that stuff and did spray it directly on the TB so that may be the primary cause, well... that and 157000 miles of use.

Just to recap - this LS3 Throttle Body (12605109 reverse rotation - gold blade) is still working flawlessly on my ls2. Once installed I put my original tune in and didn?t even so much as have to run a ?TB Relearn?. It?s running now like nothing ever happened and these TB?s are a heck of a lot cheaper than the ls2 TB (silver blade)

-Steve

(Not sure why some of my characters turn into (?) when I post from my iPhone, but it?s sure annoying)