Finally, a Working IAC Tuning Guide
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Joined: Oct 2014
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From: Virginia
Finally, a Working IAC Tuning Guide Here's my new guide on tuning IAC steps vs. effective area. I have seen MANY people simply say shift the table one direction or the other if having cold start problems. That doesn't give you an accurate number or any data to log from. Here is a complete guide on how to properly fix it using data.
https://www.youtube.com/watch?v=621b...ature=youtu.be
Hope you all like it. Let me know how it works for you.
https://www.youtube.com/watch?v=621b...ature=youtu.be
Hope you all like it. Let me know how it works for you.
Cool, it gives me something new to try with the new motor. Attached are the files I built off your video. One thing I noticed was that in my math parameter, the table at the bottom only contains two rows, it doesn't show the row for PID 2320 even though it's in the formula above.
Last edited by JimMueller; Mar 29, 2019 at 03:02 PM. Reason: Updated Math parameter
Thread Starter
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Cool, it gives me something new to try with the new motor. Attached are the files I built off your video. One thing I noticed was that in my math parameter, the table at the bottom only contains two rows, it doesn't show the row for PID 2320 even though it's in the formula above.
Try that and see if that fixes it for you.
Here's my new guide on tuning IAC steps vs. effective area. I have seen MANY people simply say shift the table one direction or the other if having cold start problems. That doesn't give you an accurate number or any data to log from. Here is a complete guide on how to properly fix it using data.
https://www.youtube.com/watch?v=621b...ature=youtu.be
Hope you all like it. Let me know how it works for you.
https://www.youtube.com/watch?v=621b...ature=youtu.be
Hope you all like it. Let me know how it works for you.
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Thread Starter
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Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
You guys are very welcome. It works a lot better than the excel method and the "slide" the whole table over method too. You'll notice it won't always be spot on, but once it's close it makes a pretty big difference in range for cold starts. Obviously the car has to be idling pretty decent for this to work well, so the normal idle tuning of fuel, spark, air and all that is much more noticeable. This is that fine tuning stuff that can really punctuate a good tune. I appreciate the replies. Glad you guys like it!
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Thread Starter
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Joined: Oct 2014
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From: Virginia
Thanks again!
I use the shift method as a starting point to get it running and help it get stable, but then have to manually adjust from there. What I've been doing is copying the IAC area table to excel,a dyn air vs commanded air table from the log into excel, and a commanded air vs IAC from the log into the same excel file. then manually doing best match. I'm very interested to try out this method instead.
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From: Virginia
You'll still have to adjust the RAF table as normal. This only gets it to where the PCM actually understands how much air it's add or taking away when it opens the IAC motor. Stock table is one thing, and aftermarket TB's are another.
I want to ask what may be construed as a dumb question, but here goes: I have noticed on a 0411 / p01 / and P59 (04 express van) the iac counts seem to be vastly different in stock forums. If I am doing a clean build I always start with what is there and see how it acts first before adjusting anything. I just swapped my truck over from a P01 to a P59, and again, the counts are vastly different. The truck still starts and idles the same, as well as coming down from wot etc. In your experience, should the #'s transfer over directly, or will/should they be different? This is the first direct ecm swap I have done, and just found this a little interesting. Thanks for any info/insight and again as I said on Youtube, great work.
Thread Starter
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
I want to ask what may be construed as a dumb question, but here goes: I have noticed on a 0411 / p01 / and P59 (04 express van) the iac counts seem to be vastly different in stock forums. If I am doing a clean build I always start with what is there and see how it acts first before adjusting anything. I just swapped my truck over from a P01 to a P59, and again, the counts are vastly different. The truck still starts and idles the same, as well as coming down from wot etc. In your experience, should the #'s transfer over directly, or will/should they be different? This is the first direct ecm swap I have done, and just found this a little interesting. Thanks for any info/insight and again as I said on Youtube, great work.
For anyone that has followed this writeup, how do you massage the data in the IAC table to the far left and far right that doesn't get remapped? For example, on the low end, I have a note (I don't know where I found it) that says place a 0 in the fourth column to the left of the lowest logged column, then interpolate between that new 0 and the lowest logged value, and fill all cells to the left of that 0 with 0. But on the high side? Fill the top column with a specific value and interpolate? Set it to a specific slope based upon the slope of the high values, etc?
Thread Starter
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From: Virginia
That's a pretty good way to do it on either end, but keep note that the high end seems to work best with a max of 310, or at least that's how mine is setup on my 102. It warms itself up no problem, don't even need to be in the car anymore to start it, even on cold days. I don't think it matters all that much, since as I understand it, the max is simply the max. Whatever that high number is, is full open as far as the computer is concerned. I know this because I can hear mine sucking the air in and it's loud lol. I would simply interpolate the data down to the last usable logged cells just the same as you were noting about the low side. The value be it 310 or 400 or whatever will only change the resolution of the table, and the slope/rate of the values.
Another note, is if you do have an aftermarket TB, like a 102 or whatnot, it makes a HUGE difference to port the backside of the IAC out to 3/8" or larger. I did this to mine and it had amazing results. It was decent before doing this, as I had the IAC values mapped pretty well, but after that I was able to make it idle stable at 600 with a 244/252 that maps out at about 75 kPa on average. It's freaking ridiculous lol.
Another note, is if you do have an aftermarket TB, like a 102 or whatnot, it makes a HUGE difference to port the backside of the IAC out to 3/8" or larger. I did this to mine and it had amazing results. It was decent before doing this, as I had the IAC values mapped pretty well, but after that I was able to make it idle stable at 600 with a 244/252 that maps out at about 75 kPa on average. It's freaking ridiculous lol.
Is there any need to mess with the IAC Park Position Airflow or IAC Reset Position? How close does idle fueling need to be to tweak the IAC Position? My last MAF log was within 2%, the last VE log says 2-3%. Alas, I'm not sure if I have my setup correct for tuning with dual widebands.
I have dual AFR500v2 widebands installed in narrow lambda mode. At cruising speed, B2 is generally up to 5% leaner than B1. The bank-to-bank lambda difference is a little higher during low MAP (<35kPa). I don't know how HPT is resolving two sensors to a single sensor parameter. Should I go back to only logging the leaner of the two banks and make fueling adjustments off that single leaner bank?
I have dual AFR500v2 widebands installed in narrow lambda mode. At cruising speed, B2 is generally up to 5% leaner than B1. The bank-to-bank lambda difference is a little higher during low MAP (<35kPa). I don't know how HPT is resolving two sensors to a single sensor parameter. Should I go back to only logging the leaner of the two banks and make fueling adjustments off that single leaner bank?