My maf tuning problems

[ovenroastedlnf]

Found the issue, just as I suspected, the intake coupler was crushed and was sealed properly. Fixed it and runs like a gem!

[ovenroastedlnf]

Alright, I'm to the point I might just give up. This is what I am doing, some one tell me if I'm doing this wrong.

Stock tune other than the Injector spreadsheet set up for 60's and 4500 in the ETC Area Scalar for the ls4 throttle body.

First I tried to tune the VE, didn't go so well. I have my pid LTFT+STFT and have it in the histogram MAP vs. RPM. Log the car for about 1/2 hour, only did cruising around. Copied the table, went into the tune, pasted by %. Flashed tune, started car, let it warm up, reset fuel trims and started logging again. Trims were closer but no where near where they should have been. Car also ran worse after each change.. Idle is terrible, bounces between 13-15.5 afr.

So I jumped over to start tuning the maf since I wasn't getting anywhere with VE. Same setup, LTFT+STFT vs. Maf Freq., did our logs copied, paste by % etc. Although the Maf ran a lot smoother, it didn't seem to read correct. It was showing right, it was
-20 around the 3k-3.5k areas but the afr on the gauge was in the 16's. Didn't make sense to me. But we kept making the changes and it got closer, but no matter what I did it never got close to 0. But it was decent so we jumped into PE.

As soon as he would push it to the floor it just went pig rich, and would buck like crazy. We rolled into it every time and adjusted the Maf accordingly. But no matter what it would still be ridiculously rich. We got it to go to 5.2k decently then it would just drop to 10.0 and fall on is face. So we had enough for one night and gave up...

I know I should do afr % error but don't you need the afr gauge hooked up to hpt? And even if we were to do that, would I just use the same VE and Maf tables like I am doing with the LTFT+STFT pid?

[Ecotec2.4]

I'm new here and learning, but I thought when ve tuning
that you paste special ADD and not multiply % like maf tuning.

[cobaltssoverbooster]

yea ORLNF u gotta paste add on the ve table and by percent on the maf sensor. make sure defco is disabled.

[ovenroastedlnf]

Well son of a bitch...I did not know that.

So I still add with the ltft+stft pid dialing in fuel trims and if I were using afr % error? Just want to make sure I have that down.

Thanks guys!

[Ecotec2.4]

my histrogram for ve is set up with General & Plot pid as stft+ltft and the Row & Col Axis set up like the ve table in the tune.
Thanks to ^^Mr. CobaltssOverbooster, great guy !

[cobaltssoverbooster]

i only organized some info from the guys better at lsj than i was. to them u should thank.

[Freakotec]

You NEED to set up your base by tuning via afr error while running purely in open loop with dfco and trims disabled. Once VE is dialed in and MAF is scaled correctly THEN you can switch back to closed loop and tweak things via trims. Just remember that once you enter PE, the pcm will enter back into open loop (even if you're set to run in closed loop) so at that point do not try to compensate any maf scaling via your trims or you will throw things off again in WOT areas (or anywhere when you enter PE for that matter). If you tune purely off of trims from the get go you will basically be chasing your tail in the dark. Hense why the wideband was reading all over the place on you.

[ovenroastedlnf]

To tune afr error, dont I need to set up the ac pressure switch and all that? I dont have hpt pro, unfortunately...

[cobaltssoverbooster]

yup

[ovenroastedlnf]

Damn, now I need to figure out the pid and all that crap for it.

[Freakotec]

Yep, you'll need to set up a custom user pid using the ac pressure switch wire for your wideband signal into the pcm and then insert that pid into your afr error pid to reference against commanded afr. Really the hardest part in getting it all working is scaling the custom user pid equation correctly in order to match the actual wideband readout on the gauge.

If you plan on making a habbit of tuning pretty much anything other than a LNF, I would personally think about doing yourself a favor and make a nice plug and play harness for a removable wideband system. The harness I made for connecting into the ac pressure switch connects in literally 10-15 minutes, including the wideband sensor install. It just makes life a million times easier IMO, but that's just the way I've always done it.

[Speedytec]

I've read before about this "adding", but still confuded about when to "add" or when to "multiply %". I normally multiply% my logged LTFT + STFT or the logged WB error% for PE, as I thought these all represent a fuelling % error?

Someone with more experience please clarify what works on an LSJ for MAF CL-trims, MAF OL-WB%err, VE CL-trims, VE OL-WB%err.


WB-AC => Very good explanation of setting up a WB PID here: http://ls1tech.com/forums/7086385-post5.html

[Freakotec]

You should always tweak maf and ve scaling via afr error. This is particularly critical for PE tuning. The pcm enters open loop when in PE so there are no "trims" to use for scaling anything what so ever. Further more, if you have any lingering ltft's in PE at all and include that in any of your maf scaling you will just further throw things off and start chasing your tail again. I've seen guys dig themselves a massive hole with attempting to tune PE with trims and throw afr error% as far off as 20% when finally checked vs a wideband. I really can't stress enough how important it is to tune in open loop using afr error% and disable all trims even for idle and normal cruising. Once you get things well dialed in for open loop with afr error%, and you enable closed loop and fuel trimming again the car will be MUCH happier and will basically need little to no trim adjustments for.

This doesn't apply to tuning a LNF mind you.

[Speedytec]

That's clear with the tuning Open Loop via WB%err and Closed Loop via trims , but still my question remains about Adding or Multiplying %

Please clarify what works best on an LSJ for MAF CL-trims, MAF OL-WB%err, VE CL-trims, VE OL-WB%err.

[Freakotec]

Sorry I missed your direct question there. You're creating an error % whether it's trims or afr error so you should always special paste - multiply by % whether it's your ve table or maf table. After you made your first big correction (multiply %) then you can make smaller corrections after that by using multiply % by half to make smaller and smaller increments.

Of course be sure to disable the maf when scaling ve and disable ve when scaling maf otherwise both tables will be fighting one another.

[Speedytec]

Multiply % what I always do/did to correct my VE or MAF tables, but this confused me:

yea ORLNF u gotta paste add on the ve table and by percent on the maf sensor. make sure defco is disabled.

[Freakotec]

Hmm, I've never added to be honest so I can't comment on that. I've always multiplied by for both. Even with using bluecat to verify some of the ve tables it always seems to work out for me on wideband readings ultimately.

[cobaltssoverbooster]

adding only applies to using the ltft+stft pid.
in the ve tables each value represents 1 trim of fuel so naturally adding the values aquired in the scanner of the active trims you will make corrections of the same base as the ve table.

the lnf for example: the base table is a percentage of the maf readings. the scanner logs them in percent. so you change the base percentages by percent.

lsj has fuel trims scan in values of trims so you change them with trims.

with afr% error you are taking the base table in an lsj and calling all the values in the flashed ve table 100%. each cell is now 100% of what is commanded. so if you command 14.7 and the afr% error says its off 2% then all you do is multiply by 1.02 to add 2% more fuel for what you were just commanding. (you scanned in percent so you change by percent) if its off -2% then multiply by .98 to subtract 2%.
when you re-flash the adjustments the new values just became the new 100% commanded value. Just make sure you multiply by percent on your corrected ve table to make proper adjustments. (make corrections-scan-make corrections to the correction-scan-repeat until done)

if you make an initial correction of 2% and flash and scan and the scan says you need another 1% dont increase the fuel by 3%. you do not add the total of all corrections together. each correction is its own based off of the currently flashed values.


as stated pe is not using trims so the afr% error is applied to the pe enrich table only. once in pe enrich - the pe enrich table is adjusted to set the commanded afr. so in your scanner you can set a custom histogram up to filter out non-pe from pe values. make the filter value track the pedal % value and set the limit to the pe threshold. depending on how you set it up you can make the histogram show afr error in non-pe only or in pe active only. Unfortunately id have to do research to find out the exact filter wording and i dont have any lsj's available which is also why i have not been able to finish the lsj tuning guide videos. When the videos become available i will be sure to include ve adjustments both by trims and by afr % error.