Tuning AFM FLOW

Civic 2016+ 1.5 Turbo
Post Reply
JJ-Civic
Posts: 6
Joined: Thu May 24, 2018 5:02 pm

Tuning AFM FLOW

Post by JJ-Civic » Thu May 24, 2018 5:14 pm

In regards to: https://www.hondata.com/help/flashpro/i ... g_fuel.htm

Using the referenced XY graph (at the bottom) as the example, It is stated:
"In this case the AFM is reading approx 15% low, and the first tuning change would be to increase the AFM flow numbers by 15%, across the whole table, and then re-test."

To me it seems as 15% high (if "0" is neutral)?

Can you confirm?

I attached a XY graph from my very first data-log. I'm not going to adjust anything until further logs but want to understand.

Thank you
Attachments
JJ-Civic AFM XY graph - very 1st run.PNG
JJ-Civic AFM XY graph - very 1st run.PNG (24.93 KiB) Viewed 856 times

JJ-Civic
Posts: 6
Joined: Thu May 24, 2018 5:02 pm

Re: Tuning AFM FLOW

Post by JJ-Civic » Thu May 24, 2018 5:19 pm

And 30 min drive home:
Attachments
JJ-Civic AFM XY graph - 2nd run - 30 minute city drive.PNG
JJ-Civic AFM XY graph - 2nd run - 30 minute city drive.PNG (29.78 KiB) Viewed 853 times

DarkCiv
Posts: 18
Joined: Tue May 01, 2018 9:35 pm
Location: South America

Re: Tuning AFM FLOW

Post by DarkCiv » Thu May 24, 2018 9:00 pm

Hi JJ!

Based in what I researched about Short Trim last month, I think I can answer this one for you!

First, you need to know basically that S. Trim is a "corrector" of your AFR. Based in the readings of your lambda sensor, It indicates If mixture is reach or lean.

Let us supose that your car is running LEAN 5% in all rev range. This information will be sent to the ECU, and the S.Trim Will INCREASE AFR by 5%, by putting a little bit more fuel.
S.Trim will correct your AFR by a +5%.
That is why lean AFR shows a positive S.Trim, and rich AFR shows a negative S.Trim. Got It?

With that information, and looking in your graphs, It is easy to see that your 2.5 k rpm has a perfect AFR.
From 1k to 2.2k you are running reach by 5 to 7 %.
And from 3k and above you get richer too...

I think that this is the point. Understanding Short Trim.

But shortly somebody will correct me, If I am wrong.

DarkCiv
Posts: 18
Joined: Tue May 01, 2018 9:35 pm
Location: South America

Re: Tuning AFM FLOW

Post by DarkCiv » Thu May 24, 2018 9:14 pm

Sorry!!!

Where you read "k rpm", change It by "Volt". Like, 2.5 k rpm is 2.5 V.
My bad.

JJ-Civic
Posts: 6
Joined: Thu May 24, 2018 5:02 pm

Re: Tuning AFM FLOW

Post by JJ-Civic » Fri May 25, 2018 4:09 am

DarkCiv wrote:
Thu May 24, 2018 9:14 pm
Sorry!!!

Where you read "k rpm", change It by "Volt". Like, 2.5 k rpm is 2.5 V.
My bad.
DarkCiv,

Thank you for explaining.

JJ-Civic
Posts: 6
Joined: Thu May 24, 2018 5:02 pm

Re: Tuning AFM FLOW

Post by JJ-Civic » Fri May 25, 2018 11:37 am

DarkCiv wrote:
Thu May 24, 2018 9:00 pm

With that information, and looking in your graphs, It is easy to see that your 2.5 k rpm has a perfect AFR.
From 1k to 2.2k you are running reach by 5 to 7 %.
And from 3k and above you get richer too...
And just to confirm :)

Using the above info, "From 1k to 2.2k you are running reach by 5 to 7 %."

I could adjust the highlighted Mass flow #'s in the example here:
AFM flow example.png
AFM flow example.png (8.12 KiB) Viewed 830 times

JJ-Civic
Posts: 6
Joined: Thu May 24, 2018 5:02 pm

Re: Tuning AFM FLOW

Post by JJ-Civic » Fri May 25, 2018 11:38 am

adjust -5% ?

DarkCiv
Posts: 18
Joined: Tue May 01, 2018 9:35 pm
Location: South America

Re: Tuning AFM FLOW

Post by DarkCiv » Sat May 26, 2018 8:14 pm

Hi JJ!

Listen, first of all I want you to know that I still don't have a FlasPro, ok! But I really like Graphs.

The answer to you question above is yes, in my point of view. This would be my starting point, if your car was mine.

But, I realized that your second graph is really better and smoother then the first one. It tells me that you took more time running the car to build that graph. So, for me, it is a very nice start. Much better than the first one. And it is much easier to see the gaps.

So, I took some time here, and build up to you a full scale that, in my opinion, you could be using on your AFM tunning. I took a ruler, and rebuild your graph, putting points every 0,1 V.

Therefore, If I were you, and your car was mine, I would start with this adjustments.

. . Voltage . . . Mass flow

1,05 up to 1,60 = -5%
1,68 up to 1,99 = -7%
2,03 up to 2,15 = -5%
2,19 up to 2,23 = -4%
2,30 up to 2,38 = -2%
2,46 up to 2,77 = 0%
2,85 up to 3,71 = -2%
3,79 up to 4,34 = -3%

First observation: It is remarkable that the graph has A LOT of points from 1,10 to 2,6 Volts. So, it is much more precise to tell the corrections.
Second observation: from 3 volts and above, there are not so much points. So I was a bit more conservative on the corrections.

Please save all your starting numbers before the change!!!!!

Finally, I want to reinforce to you that this corrections that I proposed to you is what I would start doing, if your car was mine.
I would upload this new numbers, and take another 30 minutes ride again. And in the end build another graph. Warm up your car before starting datalog. Let the ECU get used to the new numbers.

If you get a little afraid doing all this changes at once, you can start doing only one or two lines of the table above. Make a shorter ride, like, 15 minutes, and take a look on the new graph... It is better to change the part that you use more on a ride, the low voltage part.

I am really excited to see this new graph!!!
And I hope that it helps putting a better AF in your car!!!!

JJ-Civic
Posts: 6
Joined: Thu May 24, 2018 5:02 pm

Re: Tuning AFM FLOW

Post by JJ-Civic » Sun May 27, 2018 3:34 pm

DarkCiv,

Very much appreciated. Thanks for taking the time to look at this.

Thank you.

Post Reply