afr histogram not working

[86buick1]

Can someone please point me in the right direction?

I am going redo my VE tables all over using my wideband, since I have a better idea of what I am doing.
I have a PLX Wideband, already have that logging in my table section.
I tried making an AFR error % histogram (with my VE table info, and in the main section I have it trying to log AFR error. I have also tried EQ error and no luck).

I know for a fact I am doing it wrong.

Please help.
My ultimate goal is to adjust my VE tables using my actual AFR vs commanded AFR. I tried a couple of the tutorials on here and couldn't get it to work.

[TimbrSS]

Sounds like you're close.
Are you using MPVI Pro input, or other method?
You need to have the transform for the input setup as AFR if you want to do AFR histogram, or setup as EQ sensor if you want EQ histogram.
I've had to delete my wideband sensor from logged channels and then set it back up again to get the %error histogram to work.

[86buick1]

Thanks man.

Using mpvi pro input.
I have it set up for AFR. It logs my AFR great, but I actually want to use that data and compare it to my commanded afr, and adjust my VE table(s).

When I add a table and add afr error, isnt there math involved? Do I need to add a math calc that takes commanded afr and subtracts it from actual afr?

This is where I get lost. Lol

[TimbrSS]

When you make the chart, Select the parameter at the top. Then take that menu down to maths, then Lambda/AFR, the select afr error. That will do the work for you, and give you percent error from commanded.

afrerror.jpg

[86buick1]

I will try it again. What PIDS do I have to have added to my channel list for this to function? Commanded AFR, MAP, and RPM?

How does the scanner know how to use the wideband readings for AFR error? Is it already built into that specific output? That's where I get confused. If it doesn't reference the wideband, how does the computer know what the error is?

[TimbrSS]

Log AFR, MAP, RPM, AFR commanded.

(if running custom 2 bar or 3 bar OS, pick the proper 2 or 3 bar MAP sensor.)

When you enter the info when you add (transform) your AFR sensor, it assigns the ID [50120] to that sensor. When you want to math it, you just use that ID.

AFR error math: 100 * ([50120] - [50121]) / [50121]


afrmath.jpg

[86buick1]

You are the man!

I tuned the car for about 5 hours yesterday with the method you described. I was able to get a majority of the table super close (within 5% of target). At WOT it needs some tweaking, but that brings me to another question.

When in MAF mode and all my trims turned back on, driving around town everything looks good. When I go WOT, no matter what I do, the car will not hit commanded AFR. Always about +.5. If I change my EQ ratio, it will follow that by +.5. My maf scaling looks excellent, an average of -2 to -3 on the histogram (MAF and STFTLTFT). I added a bunch of fuel in WOT area of my VE tables and it didn't change anything.

When I turn the MAF off and go into SD and hit WOT, It responds just like it should. Fueling is a little wacky because it needs some finessing, but it goes rich like it needs to.

Have I run out of room with my stock MAF? its a stock LS1 MAF.

[86buick1]

ttt

[TimbrSS]

It's not responding because it's calculating airflow of the MAF, which it sounds like you didn't adjust? Log MAF frequency. If it flatlines while RPM is climbing, then it's maxed, but sounds like you just need to add to your MAF Airflow vs Frequency table. Turn off dynamic airflow so that it only uses MAF, not VE. Then you go back to open loop. Make a MAF histogram like your MAP.... Then tune that.

[86buick1]

Thanks brother. I have been adjusting the MAF table, I believe there is only one? Its a nice curve like the stocker, and when I look at the histogram its giving me small negative %, nothing positive. Should I try bringing it to 0? Or maybe just adjust it until I am golden at WOT?

[TimbrSS]

Tune the MAF open loop against MAF AFR error, not STFT, LTFT

[86buick1]

Going to do it now. Should I keep PE enabled because that is where I am trying to tune?

[Ben C]

Going to do it now. Should I keep PE enabled because that is where I am trying to tune?

Always keep pe enabled. The days of turning off pe was because people were trying to tune only with a narrow band. Now wideband are cheap so there's no reason to try and be bodgy about it.

[TimbrSS]

Yes, beauty of wideband and AFR commanded/error math makes it so you never have to disable PE. I wish we could just delete every thread that references doing so.

[86buick1]

Thank you guys. Getting closer, just a little frustrated.
I got my maf table very close, and when I decided to change the dynamic airflow high rpm disable back to 4000 (tuning it at 200, now it's all over the place again. Not by alot, but 10 percent give or take in some areas.
Should I be tuning the MAF with SD enabled or disabled?

[TimbrSS]

Is it doing that with open or closed loop? Have you been clearing your fuel trims with the scanner each time you go back to open loop?

[86buick1]

When in closed loop and trims on, it adjusts my maf error by about 5 percent in either direction. So if I was at -2 at 5000hz, now it will be around 1.3.

I dialed it in with high airflow disable at 4000, and I got the table to -4 - + .5 across the board. even at WOT. When trims are on, it skews these readings slightly like stated above.

Also with trims on, and my maf error on the money, in the 1200 to 2400 range under mid load it's taking out about 10 percent average. Stft are OK, +-5 in worst cases usually less.

Thanks so much for the help, you have gotten me very far man.

[86buick1]

In open loop I dont really pay attention, i wait for the car to warm up to operating temp for accurate data

[TimbrSS]

Don't know much about your set up, but sounds like your stock o2 sensors are throwing you off. Just search and read up on adjusting those for cam/headers.