Yeah, so the engine measures or calculates how much air enters the engine then adds fuel accordingly, so my question still stands.
By reducing the airflow the ecu will reduce fuel?
Yeah, so the engine measures or calculates how much air enters the engine then adds fuel accordingly, so my question still stands.
By reducing the airflow the ecu will reduce fuel?
That table is not a part of the fueling calculations. That table tells the ecu how much it needs to hold the iac / throttle blade open. reducing it will reduce airflow into the engine and the same tune will show richer because of the richer AFR.
So at idle does the ecu not measure airflow with either the maf or calculate it with map sensor? I thought it always measures the airflow and adds fuel to suit.
What you are implying is at idle the ecu just ads an arbitrary amount of fuel, and adjusting the airflow will change the fuelling. Which seems odd.
.Originally Posted by AutoWiz
Lol ^^
I already mentioned that in post #6 but was told "That doesn't control fueling. Especially in closed loop."So why not try to reduce your idle airflow at that specific temp?
Why not find the temp where your +20% and multiply that cell by the .95. re test and see where you are at. It's not dropping the idle rpm just closing the iac / throttle blade a little more to force a richer condition
but
your post has made me realize I was leaning out my Idle Airflow table instead of richening it (and that I was correct about adjusting this table).
I thought higher numbers = richer
Thanks guys.
Last edited by Mr. Smith; 05-26-2017 at 08:12 PM.
FFS I'm so sick of these HPT-related headphucks!
If higher numbers = leaner,
then why would the Idle Airflow table have higher numbers at cold temps and vice versa?????
Mods, please ban me from this forum.
When you want a higher idle when the motor is cold you need more airflow. The idle rpm vs. coolant temp table should be taken into consideration when adjusting this table. And any changes made to the idle speed table should warrant changes to this table because it takes a different volume of air to hold different rpm.
You be nice to eagle. I know on the surface it might look like he has spent more time with a computer than a car, or like he is over worked and in need of giving his mind a rest, But Eaglegoat is my new best friend and I must stand up for him. It wasn't his fault, he didn't know what he was saying.
Thanks. I know that the Airflow table should suit the Targeted RPMs...........
and I'm not talking about adjusting my idle RPM's..........
what I want to know is..
How exactly do I richen up my warmup fuel trims in CL????
Do I raise the Idle Airflow table numbers or lower them? Any other tables? How can I richen off-idle RPMs?
In one post I get "don't bother adjusting the Idle Airflow table" then I get "why don't you adjust the Idle Airflow table" then I get "closing the throttle blade a bit to restrict airflow" then "you want more airflow when the motor is cold".....
Man, I can never get a simple answer.
Here's a pic of my current idle airflow settings
Idle and Airflow.jpg
I am trying my best to keep things simple and understandable. That table controls the iac or throttle blade on drive by wire and more airflow means more airflow. So lets say your problem of +20stft is at 44c. Ok your showing 9.70 there, so you would take that 9.7 and multiply it by .9 giving you a 10% reduction and then change that cell to 8.73. flash it to your ecm, reset fuel trim data log some data and see if the problem gets better.
So I have to lower the numbers in that table to richen things up. Okay, thank you.
The idle airflow table has nothing to do with air fuel ratio. Even if you change that table the PCM is just going to relearn where it needs to operate the IAC to maintain ile speed. You need to look at other fuel multipliers.
When the engine is cold it has alot more friction to overcome. Along with the higher friction and higher idle speed means more IAC opening. This alters where the engine is running on both the VE table and MAF table. If it is running lean in those areas fatten it up a little. I shoot for all negative trims in my tunes.
You were told that because that table doesn't control fueling. If your VE and MAF tables are tuned correctly, at operating temperature, then the PCM will add fuel based upon how much air is entering the engine. It doesn't matter what you change in these tables the PCM will adjust what it does to suit.
You're a moron. Every time you post the dumb things you post you continue to show the entire world how ignorant you are.
The only way to accomplish what you're looking for is to raise your closed loop enable temperature and then make adjustments to your open loop warm up fueling table.
You're trying to "fix" something that is a perfectly normal. The fuel doesn't atomize as well when the engine is cold (that's why GM sprays on the back of the intake valve to help with atomization). So some of the fuel you are spraying into the engine isn't burning because it's not mixing well. The lack of complete burn and the fuel going out the tailpipe both show as a lean condition. The o2 sensors see this and add more fuel to achieve stoich. Even though this is a false lean condition.
Unless this is causing an issue I highly recommend you let it go. If you are having issues (other than your cold start closed loop trims) than you've been given lots of good advise on how to fix it.
YES!!! THANK YOU! FINALLY YOU HAVE SEEN THE LIGHT!!!! Yes it will learn or rather TRIM itself back to where it needs to be. And trims ARE this man's problems. He is not looking to change a closed loop commanded afr. He is worried about fuel trim data at different points of temperature. And this is how he can adjust that. And even if ok EVEN IF IT IS a "fix", at least it is an effort in the direction this man is trying to get.
Last edited by AutoWiz; 05-27-2017 at 02:48 PM.
It won't do anything to fix the issue he is having!!!! Which is why I said he needs to look at his VE and MAF tables during warmup. Fatten them up slightly in that area.
When I am tuning fuel I usually do not even start datalogging until the coolant is up to temp unless I am working on cold start/warmup.
The MAP and MAF values during warmup idle will be higher than warm idle and likely in am area that you will not really see in normal driving.
You want to datalog the idle airflow in average form from cold start through warm in Park/Neautral with all the accessories turned off from as cold as possibly then use thise values in the Idle airflow table. Then repeat the next day, drop it into Drive as soon as the engine fires and datalog that for Drive idle airflow. Once you have those set you leave them alone. Done properly the idle adapt values will read very low numbers. Then you compensate for accessory load like the a/c compressor through the a/c torque table. It will the best most stable idle possible.
Thank you very much gents for your help, time and detailed replies.
I will play around with my Idle Airflow then maybe my Afterstart Enrichment Initial Adder vs ECT table and if they don't improve things (which I doubt), then I'll just leave it. If I can bring my cold +20 fuel trim cells down to +10 max., I'll be happy with that.
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