HPtuner tuning with LTFT and STFT???

**Firebirdjones** · 01-26-2008, 04:16 PM

Been using LTFT's for dialing in the VE tables and have had great results so far.

I am thinking about trying to do it with STFT's since I hear from people that it's faster????

Is there anything different I need to do???

All I can think of is obviously I just simply need to log STFT's in the histograms,,,,which is already setup to do so.. and just copy/paste/multiply to the VE table just like I have been doing with LTFT's... Am I missing something here???

**Frost** · 01-26-2008, 11:19 PM

disable LTFTs in the editor and when you first connect the scanner, use the VCM control to RESET FUEL TRIMS. If not, any previous learned active LTFTs will still apply themselves.

**Firebirdjones** · 01-27-2008, 04:47 AM

After that it's pretty much the same procedure??? Copy/paste/multiply% right?

I find it interesting you noted reset the fuel trims or any previous LTFT's that have been learned will still apply,,,,thats an interesting tid bit I wasn't aware of.

Whats the best way to disable LTFT's?? I am guessing I will have to do that in the tune and flash that to the car before I begin???

Or is it something I can temporarily do while I am scanning???

**Frost** · 01-27-2008, 05:47 AM

No disable them in the editor & flash and update

**Firebirdjones** · 01-27-2008, 07:15 AM

Okay I'll give it a shot,,,thanks, I appreciate it.

**mrr23** · 01-27-2008, 07:20 PM

i've been doing closed loop STFT SD tuning on the 408 for about a month now. about ready to turn the MAF back on.

**Firebirdjones** · 01-28-2008, 03:22 AM

Originally Posted by mrr23

i've been doing closed loop STFT SD tuning on the 408 for about a month now. about ready to turn the MAF back on.

Man I can't wait to have weather like that to be able to tune year round. I am interested to see how the STFT's do for me.

**Frost** · 01-28-2008, 04:18 AM

they do fine until you need to calibrate things for WOT.

**Firebirdjones** · 01-28-2008, 04:55 PM

Originally Posted by Frost

they do fine until you need to calibrate things for WOT.

Thats good to hear. I have always used LTFT's,,,but I had to drive around quite a while to get them to settle in,,,make changes in the VE and start the process again.

I have had good success this way with no problems,,,I just thougt I would try STFT's and see if things are easier or quicker per say.

The car has been pretty close with -1 and -2 fuel trims but I recently installed headers so I want to touch it up a bit. Shouldn't take too much.

I haven't done the wideband tuning yet,,,so my PE table is still stock,,,,I'll hook that up and play around with the PE after the VE tables and MAF tables are decent I guess.

I struggle on that stupid MAF table though,,,,UGH!

**Frost** · 01-28-2008, 06:05 PM

Fuel trims are a good place to start and get you into the feel of how things work in the PCM and commonly useful to touch things up. Short term fuel trims make for much more accurate VE tuning as their correction is closer to cell correction (IS cell correction if logs require large hit-counts to show up like 35 or higher) than the LT trims. The LT trims learn and apply to whole "blocks" of cells.

Go ahead and drop the coin on a wideband, your tuning will be near perfect quick.

The MAF is EASY and much easier even with a wideband, and will you get to reaching the fueling you command in PE in no time flat.

Make a histogram as I have laid out below in your scanner, under the setup I included what it looks like in the histogram. Once you are done logging, highlight and copy the result and paste-special multiply-by-% on top of your MAF table in the editor and voila. The MAF controls most of your fueling anyway. You will likely find that you will be operating in the 3Khz to 7-ish Khz range. The bottom of the table is very touchy. Make sure you are logging MAF FREQUENCY in the table display in the scanner and STFTs of course. Here is the pic:

**Firebirdjones** · 01-29-2008, 07:13 AM

First let me say I do have an Innovative Motorsports wideband,,,I use to tune carbed cars all the time.

Problem here is my HPtuner software is not the software that is compatable with the wideband,,,so I have to use it seperately, mainly to make sure the PE (WOT is safe)

I do have my MAF histogram just as you have posted. With only one difference.

Where you have,,,,maf3_v6,,,,,I don't have that option,,,,mine is just MAF.
(I suspect it's because you are using a wideband???)

Otherwise it's identical, and works fine,,,what I meant about dreading tuning the MAF I will try to describe as best I can.

While logging I can watch the histogram and how it follows the throttle/rpm and fills the spaces....then I copy/paste/multiply% right over to the MAF tables,,,thats easy enough,,,but my complaint is

I cannot fill the MAF histogram entirely without hitting PE mode,,,which I understand skews the numbers,,,much like VE tuning...

All the reading I have done states while tuning MAF to just load the car down low (maybe 3rd gear) wack the throttle and run the motor through it's rpm range (to 6,000 or so) and then copy/paste

My problem with this theory of tuning is what happens to PE mode???? Once it's enabled won't the numbers be skewed???

All I did on my MAF tuning was try to keep the rpms below 4,000 rpms with moderate throttle changes and stayed out of PE the best I could,,,so alot of the MAF tables were never reached.....( I delayed my PE for MAF tuning to 4,000 rpms and I think 80 KPA)

Is there something I'm missing here??? Any other idea how to go about it??? I have been a little hesitant to disable PE all together. I have already delayed it as far as I care to try for MAF tuning...

Or maybe PE mode isn't a factor while MAF tuning???? Just guessing here,,,I don't know how others are doing it.

**Firebirdjones** · 01-29-2008, 07:28 AM

One more quick stupid question,,,,How do I go about disabling LTFT's in editor so I can tune with STFT's in the scanner???

**Frost** · 01-29-2008, 07:36 AM

There is just a pulldown tab to disable them; no temp settings like general CL.

Mine is called maf3_V6 simply because that is what I named it...

You are right, most of it is untouchable out of PE (though your VE is the same way). That is why you need to log with your WIDEBAND, especially if you have one already.... why even bother with the MAF and fuel trims if you already have the wideband? All you have to do is log AFR commanded and plot it against what your wideband says and it will fill the MAF histogram with % error that is comprised of actual vs. commanded fueling. Doing it like that, it doesn't matter if you go into PE... heck you HAVE TO. After you make about 3 pulls in a higher gear and apply the % error back to the MAF table, you will find that you are hitting your commanded AFR in PE.

**Firebirdjones** · 01-29-2008, 07:53 AM

Well I have never tried to log AFR commanded and don't know how to setup the histogram for that or how that would transfer over to an MAF table..

Since the histograms came setup from the get go with LTFT's and STFT's it seemed the thing to do.

How would you set up a histogram to follow AFR commanded???? This only works for MAF tuning correct???

**Firebirdjones** · 01-29-2008, 07:59 AM

I'm looking at my MAF histogram again,,,,,I have my plot value set to LTFT

So I guess it's reading the LTFT's and coming up with the corrections.....

Would it make more sense to change the plot value to STFT's if I use the fuel trims for corrections??????

I also assume changing this plot value to AFR or is it AFR commanded would allow it to read for AFR corrections?????

**Firebirdjones** · 01-29-2008, 08:28 AM

Going back to a previous discussion,,,I can't seem to find any pulldown tab anywhere to disable LTFT's for VE tuning

**Frost** · 01-29-2008, 08:49 AM

LTFTs just have an enable/disable tab under fueling....

You need to log AFR error in % against the MAF, I don't have it in front of me, so I can't screen shot the scanner like I did last night. Goto HPT's forum and look at posts by Russ K, I know I have seen him post a MAF AFR error config for people quite a bit. And heck no it's not just for the MAF, it's the fastest way to do your VE tuning as well.

**Firebirdjones** · 01-29-2008, 09:01 AM

Originally Posted by Frost

LTFTs just have an enable/disable tab under fueling....

You need to log AFR error in % against the MAF, I don't have it in front of me, so I can't screen shot the scanner like I did last night. Goto HPT's forum and look at posts by Russ K, I know I have seen him post a MAF AFR error config for people quite a bit. And heck no it's not just for the MAF, it's the fastest way to do your VE tuning as well.

Ya those screen shots are what I need to set up the histograms properly. Hard to find someone willing to do that. I appreciate what you have done so far.

**Frost** · 01-29-2008, 09:32 AM

I won't get home for another 8-ish hours, the answer to every question you ask can be found on HPT's forum in multiple places. As I said, Russ K has cfg files and hst files (whole histograms) posted in LOTS of places over there. Just search for his name and MAF tuning. http://www.hptuners.com/forum/showthread.php?t=15430

**0rion** · 01-29-2008, 11:16 AM

what screen shots are you looking for in particular? I've heard of people logging their wb's through the a/c since it's 0-5v also. I'm not sure how that works out for people but it's something to reasearch and see if you can use. It's really nice to log them side by side. I used to log them seperately back when I had edit, PIA for sure. Let me know what screen shots you want and I'll post them up.
I would definitely figure out a way to log that wideband with hptuners. It makes afr tuning way easier. No more trims to worry about. The only thing I noticed was variations due to weather conditions which made the afr fluctuate a lot more than I thought it would. I would even look and see about upgrading to the pro version of hptuners at some point.......well worth it.