VE Tuning Issue

[PGA2B]

My first attempt at tuning the VE went well and fixed some bogging (Lean issues) I had. But now after further tuning the VE no matter what I do it is showing lean on my STFT's and VE graph and getting worse. I adjust the Fuel Tims & VE table richer and it gets leaner?

I have been reading the threads on VE Tuning to educate myself but can't seems to find any on my issue and what I am doing wrong.

[avido]

i had the same problem and i discovered i had an exhaust gasket leaking

[PGA2B]

So I think my problem is I made adjustments to my MAF table to correct the lean STFTs while also changing the VE table. Would that contribute to the lean conditions? Thinking about it with the MAF disabled the changes to the MAF table shouldn't have changed anything? This is really messing with my confidence in what I thought I knew.

[avido]

of course i have to fail the maf to tune the ve and disable the ve tu tune the maf.

[DGS]

You can't do both at same time. Fix MAF, then VE. Also, the VE tables show only changes to first table. Change all four under VE mode at upper left. Then click Calculate Coefficients after each table change before opening the next. On VE log, you can't have any 02 inputs or it will skew the WB values. Disable all fuel inputs. Must be open loop. For MAF tune, you don't want any PE input. Raise PE RPM and easy on throttle. There my be other adjustments. Not sure on your vehicle. I would look at similar posts with tunes and compare. Did not see any chart setups so don't what parameters and ranges you picked to make sure they match your VE table.

[PGA2B]

I used the data gathered from the VE histogram and built the first table then copied the table. Then hit calculate coefficients then went to the next table pasted the original table hit calculate coefficients and so on for all 4. Am I suppose to use the result from each previous table as the base for the next table? Also I am using STFT to calculate the table. I added my config file.

[DGS]

No on re-using result from prev. table. On the MAF tune above I looked at the VVE tables (Edit - VVE) and saw a change in numbers from first table to second one. It appears the first one has not had the changes made/saved to it or you changed the first one and not the other three. I know it's tedious and easy to forget to Calculate. I catch myself from time to time. I would re-do. Any chance you could provide the chart(s) to view the set up? Also make/model/year/eng.. I had same issues. I found was using WB error and was skewing data in charts causing rich vs. lean changes or lean vs. rich to my VVE table. The WB needs no modification or math calculation. The results are exact. I'm using MPVI2 and newest AEM OBD2 WB set up. No one yet has commented specifically. I think they are used to tuning older vehicles with VE tables, not VVE tables. I not sure they understand the real issue. If you set up using the posted methods, you'll run into what we both have described. The new GM ones are more complicated. You can search my VVE posts and read. Let me know what you find. Maybe we can combine knowledge and totally resolve. I've worked on vehicles for decades and I am still learning the tuning side.

[PGA2B]

Here is my 1st log after setting it up for VE. I just looked at the MAF file and i didn't change the other 3 back to stock. The first table is stock. I was going back and starting again. Car is below but it is a 2013 CTS-V 6.2 SC

[07GTS]

is the lean spot during a transition ? i always try to use throttle as smooth as possible to go as far as i can around the VE table and use filters to remove transitions so u keep the best steady state data, if u use some throttle then cause a lean spot u can adjust the transient fuel also impact factor and or evap to help tip in/out

[DGS]

Of the two log files, which one is the first so I can re-create on my computer with your charts and parameters and play the log? I disconnect evap purge connector to eliminate any other incoming fuel/air. That way MAF is reading only what is passing thru the MAF.

[PGA2B]

The lean spot was real as i filter out throttle changes over +/-5% as well as 200ms before change and after. I also filter all decel fuel cell data.

The MAF is disabled as I am working on VE. I just included both tunes to show what I have disabled on each.

[50090.156.slope(200)]<5 AND [50090.156.slope(-200)]<5 AND [50010.242]>104 AND [50121]>14.5 AND [6310]<7 OR ([6310]<14 AND [6310]>7)

VE log is too big. If you can IM me your email I send it your way.

[DGS]

https://forum.hptuners.com/showthrea...s-to-VVE-Table

[PGA2B]

I'd pull your email. And thanks for the link. I'll read it.

[momotunes]

Hello,

Can you post a copy of your tune? I had this same problem a while back.

[DGS]

So what was the solution? My questions are: Will the positive and negative trim/02 numbers automatically calculate correctly when using the "Paste Special Multiply by %-Half" to the VVE table or are the negative numbers in some cells throwing it off. Why would I get the opposite result? No one has really answered, but maybe I haven't asked this exact question before. I've seen comments of multiplying the whole VVE table by 10% to richen the whole tune first, then log and paste results. Is this to make sure everything is rich and then the math works when using "Paste Special Multiply by %-Half" because there are no negative trim/02 numbers? Or was it due to using a WB error chart by accident with a WB sensor when logging? I don't have access to HP Tuners "math" they designed into this calculation. Am I making the mistake of thinking I can past the whole table of cells at once from a log? Do I have to paste each positive or negative cell separately to ensure fuel is changed in the lean or rich direction by using a different calculation? Here is a tune from awhile back. I've done this numerous times. I did not go over with fine tooth comb, but I believe this is in open loop with no trim inputs. Another question is: If I am logging channels , but not using in the charts and graphs, am I polluting/skewing my data? My thought was log everything possible on my test drive and then I could make pretty much any chart from the same log w/o having to drive again. Of course, I realize if I'm doing a MAF tune vs. VVE tune, I would need to set up the tune to disable the correct inputs? I'm using 4.2.1 version and /or beta now so I haven't tried this again with the new updated software. Maybe there were errors in the software or my own errors. Thanks for the input. I have posted numerous times under VVE. Maybe you can make sense of it by looking at my posts.

https://forum.hptuners.com/showthread.php?74361-Applying-Changes-to-VVE-Table

[momotunes]

So what was the solution? - I didn't have the MAF failed correctly :-(..
My questions are: Will the positive and negative trim/02 numbers automatically calculate correctly when using the "Paste Special Multiply by %-Half" to the VVE table or are the negative numbers in some cells throwing it off. Why would I get the opposite result? - -------------------------- - Yes. For added peace of mind copy everything in excel and run a formula. Sometimes after a flash the VVE will read incorrectly. Drive for a few and things even out. I don't know why but something I've noticed. Also, make sure your graph in the scanner matches your VVE in the tune exactly. Make sure your scanner is set up to match unit measurement too. For example, VVE will show pressure in KPA. Make sure scanner is reading that too. You did fail the MAF in the tune correct? Make sure MAF frequency fail high is set to "1". Along with setting your dynamic airflow high rpm disable and re-enable to a high value. (I'll review it later tonight if not tomorrow afternoon.
No one has really answered, but maybe I haven't asked this exact question before. I've seen comments of multiplying the whole VVE table by 10% to richen the whole tune first, then log and paste results. Is this to make sure everything is rich and then the math works when using "Paste Special Multiply by %-Half" because there are no negative trim/02 numbers?
Or was it due to using a WB error chart by accident with a WB sensor when logging? I don't have access to HP Tuners "math" they designed into this calculation. Am I making the mistake of thinking I can past the whole table of cells at once from a log? Do I have to paste each positive or negative cell separately to ensure fuel is changed in the lean or rich direction by using a different calculation? Here is a tune from awhile back. I've done this numerous times. I did not go over with fine tooth comb, but I believe this is in open loop with no trim inputs. - - - - -Yes you multiply by so much from the start to protect your engine from running lean. What "math" do you not have access too? If your missing something just add it yourself in the scanner. You can paste special to your VVE all at once it will figure everything correctly. Sometimes I find it easier to paste the scanner data into excel and weed out the junk. Such as if you have three cells, the two outside are showing rich and the middle cell is showing lean I'll delete it from excel. This is of course unless I know for sure it wasn't a lean spot. You can copy the data from excel and paste special to the VVE.

Another question is: If I am logging channels , but not using in the charts and graphs, am I polluting/skewing my data------ No I do this too. Just don't log too much at one time. This can slow things down and cause data to be delayed.

I'll look over everything soon. Sorry for the wait.

[DGS]

Thanks for the reply. What I meant by not knowing the math in the "Paste Special Multiply by %-Half" was if it could actually calculate a negative number without producing the opposite result to the VVE table. When you get weird results, you begin to question why? Just want to know I can trust the results. I like the idea of using Excel. It make sense that logging to many channels can slow the data. Do you adjust the polling interval to the fastest speed or leave at defaults? I appreciate looking over this. Thanks again.

[lukearmstrong1990]

the paste special % function simply uses the positive or negative percentage error calculated by the scanner and applies that to the respective cell in the VVE.

when you paste special mult. % you're inputting the scanner data into the VVE table directly and changing it by the error %. if cell A10 in the scanner logs -8% error then cell A10 in the VVE table will by multiplied by 0.92 if your paste special % or by 0.96 if you paste special mult. % half.

if your scanner error graph axis points don't exactly match the VVE table then the calculated data you're logging will be editing the wrong sections of the VVE. be aware that your VVE table and an actual VE table for custom OS speed density are opposite on axis label.


having your scanner error graph requiring too little or too many hits to populate a cell can also lead to poor final data.

[PGA2B]

Funny thing, I did a VE log using my VE tune and applied it to my VE table and this time it didn't change the entire table like last time. So I don't know what I did wrong last time but everytime I calculated the coefficients the entire table changed no matter how little or big the change so I thought that was how it was supposed to be. So I'm gonna load it and check the log tomorrow.

[PGA2B]

Ok, so the way I was changing the VE table and interpolating in HPT was all wrong. The tune I made yesterday from logging worked and corrected the table a bit and it actually made it richer. Scanning today confirmed that my trims are coming in line and much less positive. Oddly enough I also picked up 1.6 mpg in the process. Now going to try to figure out how I screwed up originally.