Clarification on Coyote MAF tuning

[SultanHassanMasTuning]

^ its the same as your tuning stft, as mentioned, create a histogram and select PID LTFT and MAF Hrz and all you have to do is copy paste. repeat until your 1-2% off target

[txcharlie]

Thanks Hassan! I will give it a try.

[txcharlie]

I have enabled LTFT and created a histogram to get the average of B1 and B2, LTFT. I drove over 40 miles before I began logging to give the PCM time to make plenty of corrections.
I am amazed at the difference between what the STFT and LTFT histograms showed. The LTFT Histogram showed from .87 to .98. The STFT Histogram showed from .95 to 1.07. Maybe the LTFT learning being enabled throws the readings off.
I am going to make 2 more drive logs, before I change anything.

[txcharlie]

Best is to create custom pid that will make stft+ltft and you don't need to disable anything.

Do you mean the average of STFT and LTFT?

[caniggia]

I mean sum, not average.

[txcharlie]

I mean sum, not average.

I don't follow you. On my last log my stft was .96 and ltft was .95 at a specific Period. If I add them together I get .96 + .95 = 1.91. How do I use 1.91 as a correction factor?

[caniggia]

I use sae. In this case when you create custom pid but first it need to converted to percent, what is easy.

[David Borden]

Charlie, Are you using 2.24 or 2.25 to log your MAF? If 2.24, what is your PID number? Im not seeing MAF Hz, or MAF Period in either scanner, so wondering if Eric hasnt added it I thought he did to the crate PCM.

Caniggia, someone posted SAE isnt supposed to work as its not MAF Period?? Have you been successful in getting it to log and make useful corrections?

I started a thread here: http://www.hptuners.com/forum/showth...Example-within

Can you tell me if what I posted at the bottom of the thread will work?

David

[caniggia]

I have no problem, use maf hz converted to period with custom pid and sae fuel trims, i use 2.24 for that, works good, most of are v6 here, but it should work this same, if not an you have only sct type fuel trims, read bellow.
In previous model logged by sct also were numbers like 0.95, 1.03, but its still same, just have to understand it.

In sct or direct internal trims convention, stft bellow 1 means system is adding fuel, but ltft is opposite, values bellow 1 means that system is removing fuel.

SAE -10 ltft SCT 0.9
SAE 10 stft SCT 0.9
total SAE=0

so to have percent of ltft plus stft in sct style use conversion like this totalfueltrims=(1-stft)+ltft so 0.1+ltft=0

[txcharlie]

David, I use Livelink to log and use histograms. It's easier to me than to try and figure out what works and doesn't work in the HPT scanner versions.
MAF Period is working in my scanner.

[txcharlie]

I have found a formula using LTFT and STFT. This is supposed to work on coyotes. (LTFT + STFT)-1. Has anyone used this before?

I found the formula below, but it is for 3v and not coyotes.
(LTFT-1)+(1/STFT-1)+1.

Well, I'm thoroughly confused.

[David Borden]

OK thanks Charlie. Man I hope I can figure this out without other hardware. This is starting to get old...

[SultanHassanMasTuning]

soon we all hope the scanner will be up to date.

if you are looking to combine (STFT+LTFT)/2

[caniggia]

Add 20% fuel to maf, put tune in and pust log when long trims are stabilized. Then I'll tell You if my formula is correct in what i belive.

This applies to copperhead pcm....If you have .9 STFT, it means the pcm is pulling ~10% because it's running rich. A 1.1 STFT would mean it's adding ~10% fuel because it's running lean.

Most of the stuff you read about in books and see on videos, doesn't apply to the coyote. With copperhead pcm your STFT is the correction factor.

Maybe this is the problem that You think opposite? If you have 0.9 STFT pcm is ADDING 10 percent of fuel, ltft is opposite, 0.9 means removing.
It's what I posted above.
That's why you say it's correction factor is if we say about STFT only. If car is running 10% rich, you get 0.9 stft and then you applay it as factor, so it will remove fuel. It was working always this same way in SCT, also 3V.

Use 2.24 and SAE LTFT+STFT and you are done or in sct totalfueltrimsinpercent=(1-stft)+ltft

[AKDMB]

Could you simply do lambse/measured lambda?

[txcharlie]

OK thanks Charlie. Man I hope I can figure this out without other hardware. This is starting to get old...

Welcome to DIY tuning!

[wbt]

soon we all hope the scanner will be up to date.

if you are looking to combine (STFT+LTFT)/2

I'll report back on this method in the next week or so once I can load and log the changes.

[txcharlie]

Could you simply do lambse/measured lambda?

Yes, that should work too, but so should using STFTs. I would like to know what's the most accurate way of doing it.

[wbt]

I did some logging on a TVS car tonight using the latest beta build and scanner. I logged stft, ltft and MAF period at steady state RPM's. Idle, 1500 and 2500. We then did some steady state RPM logging on the road. I was able to map the period and ariflow, monitoring stft and get everything within 1-2% for bank 1 and bank 2. This car also has the JLT big air intake on it. Idle improved, driveability improved, WOT looks great. Points in the trims before were 3-6% off at places.

I would say this is a success.

[bluegoat06]

Either way should work, STFT's with LTFT's disabled, LTFT's only, or average of STFT+LTFT's, you're applying the fuel trim error% anyways to the MAF period, to derive your MAF curve according to what the fuel trims are adding/removing from your fueling in close loop.
Positive LTFT's should indicate the pcm is adding fuel, cause you're running leaner than stoich, negative LTFT's would be the opposite, PCM is removing fuel as you're running richer than stoich. STFT's work exactly in the same way, they just happen to move a lot faster cause there is no history to build from like LTFT's. if you have LTFT's enable, why worry about what the STFT's are doing ? once in close loop, they'll be the closer to stoich you can be, with LTFT's enable, just look at LTFT's and forget about STFT's.