Gen 3 VE Tuning

[svl208]

I have googled it! I googled it so much that it gets confusing! Lol!

I google it and don't feel I'm getting a completed process and result with the process I'm looking for?

I'd like and appreciate any information on tuning Gen 3 VE tables using short term fuel trims. I'm interested in anyone's full process of tuning Gen 3 VE tables from start to finish. The histogram used, Logging, The correction, and final result. As much information anyone would like to provide on their preferred process to achieve desired results.

I'd like input from whoever would like to post on this thread.

Thank you for you time.

[horsepowerguru427]

First, Sorry for the long response. Hopefully, this will be helpful to some of the new guys. This is going to cover just VE/MAF tuning, no other tune adjustments (PE, WOT tuning, Trans tune etc.) This is going to assume its a factory tune and a stock vehicle since you didnt specify (using a P01 2002 Z28 LS!). Theres not just ONE WAY to tune. There are several ways and some ways work better for some people. Results vary. There are several tuners who only use wideband information and no fuel trims. Some people use OLSTFT and some even prefer closed loop tuning. Theres other ways and theories and im sure everyone will chime in with them. Just referencing one of my personal vehicles that i basically have unlimited time with, I tune OLSTFT until I'm happy with the STFT error. Then I'll Reneable closed loop and tune LTFT+STFT and then use this data to alter what ive already done to the VE table or MAF until percentages are under 4% (I usually end up around 1-2%err)

Tuning VE
Disable MAF - Engine>Airflow>Dynamic>High RPM disable> set to 8000 (Alternatively you can or use in conjunction with Airflow>Dynamics> Steady State>set the Lo/hi Map and Lo/hi TPS to 0's (zero's), this will force the PCM to use only the VE table.)disable max line press.jpgYoull want to make sure these are set to disable when MAF is failed as well so your trans doesnt shift rough. My 02 Z28 was disabled in stock tune (btw)
Engine Diag>Airflow>MAF Frequency Fail High>set to 400
DTC's P0101,P0102,P0103 Set to error on 1st and leave the SES enabled. The PCM needs to see that DTC set immidiately and realize the MAF has "failed" so it will be running STRICTLY on the VE table.

At this point I'll disable my LTFT and closed loop mode:
Engine>Fuel>Oxygen Sensors>Closed Loop Enable>ECT vs IAT> set table to something high like 260
Engine>Fuel>Oxygen sensors>Long Term Fuel Trims>set to 'Disable' and Min ECT under that can be raised to 260 as well.

Dpending what the ambient temp is that day (lets say 70F) Ill set my OL Fueling table to "1.00" across the board so i dont have to worry about anytype of fueling adjustments being made in the background by that table. If the ambient is colder then i might just set it to "1.00" in the OP Temp range (160+) and leave the rest of the table alone. this means no logging until you reach that engine temp and AFR settles.

There are debates on turning PE off or keeping it on. It just depends for me. A lot of stock tune trucks have settings that basically dont allow PE to activate until a dumb amount of criteria are reached, so i dont see a problem with keeping PE off to do a few pulls usually. Again, this depends on the setup. For a stock car i wouldnt worry about it. NOT For something modified, ESPECIALLY in something that you havent tuned the WOT and PE.

COT and DFCO need to be disabled also. I usually copy the High octane table into the Low octane, but strictly for the purpose of keeping a more steady spark reference while tuning. Once fuel tuning is done then Spark tables need to be adjusted from stock to whatever works on that setup/vehicle.

At this point (i think i covered everything in the tune), Save the tune changes to a different file name and write that tune to the PCM.

SCANNER
First, you need to log channels of every PID youll need. If a table has an axis of 'RPM', then log RPM in the channels. If a table has an axis of 'MAP (kPa)' Then you have to be logging the MAP PID in units of kPa. If you need fuel trims in a histogram, then you need to be logging 'Fuel trims'. See a trend here? There are already predefined Fuel trim histograms in the scanner. Go drive and collect data trying to keep you foot as steady (no pedal movement) as possible. Get a 20-30 min log of all different driving conditions (NOT WOT). 3000RPM uphill is much different load on the engine than 3000RPM downhill or on flat ground. Fill as many cells as you can in the histogram.
Filter for the histograms should be applied to keep trash out of the data. Im not going to get into this, but basically, not all data is good data. Research filters and figure out what you like to use for your tuning method.
Take the data from the histogram and copy it. Go to the VE table. Paste special - Multiply by % half. Now at this point, i go through and Interpolate areas of the changed data that didnt get logged in the histogram. Interpolate VE areas after paste.jpg Remeber that you want to interpolate from a cell of known good data to another cell of known good data. The numbers in between will be set into a linear pattern based on those two selected cells. Based on the picture, You would end up with something like this VE after interpolate.jpg

Rinse and Repeat. Go get more data. Input the data. clean data in the table up. Once you are getting fuel trims in the <4% range(ish) or something youre happy with, then you can tune MAF.

MAF Tuning is the same thing. Put DTCs back to stock, MAF High Frequ fail back to stock (13,500htz), High RPM Disable> set to 400RPM.
Same procedure after setting the tune this way. Collect data, input, cleanup. MAF tuning is generally a lot faster and get dialed in quickly. I'll do a 2nd gear "pull" with low throttle input so it hits almost every cell in the MAF table. Do that and input the filtered data to the table, clean it up and do it again. Usualy 2 or 3 logs and this way and thats all the data i need.

Set all the settings back to stock and go drive and log everything. watch fuel trims and see if they stay true to what you wanted. Im sure i missed some stuff but feel free to ask any questions.

[svl208]

I'm lookin to learn on a 2007 Silverado Classic 1500.

My truck runs in only short terms and VE. No MAF. I'd like to know how to use the short terms to adjust the VE Table.

Thank you for the input.

[svl208]

Are u talking about the STFT / STFT histogram?

Thanks.

[SiriusC1024]

I have googled it! I googled it so much that it gets confusing! Lol!

I google it and don't feel I'm getting a completed process and result with the process I'm looking for?

I'd like and appreciate any information on tuning Gen 3 VE tables using short term fuel trims. I'm interested in anyone's full process of tuning Gen 3 VE tables from start to finish. The histogram used, Logging, The correction, and final result. As much information anyone would like to provide on their preferred process to achieve desired results.

I'd like input from whoever would like to post on this thread.

Thank you for you time.

Here's how I do it. There's a couple things going on in this thread, but if you start at Post #71 you can see an approach to VE tuning.
https://forum.hptuners.com/showthrea...-by-What/page4

Problem is for a 2007 Silverado that's going to be Gen IV and you'll be working with VVE. This method is great. Tune MAF and VVE simultaneously. Don't have to adjust settings to force either mode:
https://forum.hptuners.com/showthrea...-the-Same-Time

[horsepowerguru427]

Here's how I do it. There's a couple things going on in this thread, but if you start at Post #71 you can see an approach to VE tuning.
https://forum.hptuners.com/showthrea...-by-What/page4

Problem is for a 2007 Silverado that's going to be Gen IV and you'll be working with VVE. This method is great. Tune MAF and VVE simultaneously. Don't have to adjust settings to force either mode:
https://forum.hptuners.com/showthrea...-the-Same-Time

I agree, on a Gen4 this method works out very well and much less time consuming if setup is correct.

[horsepowerguru427]

I'm lookin to learn on a 2007 Silverado Classic 1500.

My truck runs in only short terms and VE. No MAF. I'd like to know how to use the short terms to adjust the VE Table.

Thank you for the input.

Well, what i wrote is pretty much talking about Gen3 LS since there was no specified vehicle and the title says Gen3 VE tuning. If youre tuning a Gen4 you COULD do it similar to what i said, but again, the MAF/VVE at the same time (like Sirius said) is the best way to do so. And yes, if youre wanting to tune from fuel trims just use the stock fuel trim histograms, but also make one that is LTFT+STFT in cutom math and use that as the "Z" axis instead of "STFT" or "LtFT".

[svl208]

My apologies. Let me clear it up.

2007 Chevrolet Silverado Classic 1500 2wd 6.0L

This is a Gen 3 vehicle because it the old body style. It was a 4.3L swapped to a 6.0L LQ4 using the original PCM.

Thanks for all the input and information.

[bk2life]

Hopefully, this will be helpful to some of the new guys. .

thanks for writing this out, it's helpful for everyone

[svl208]

"And yes, if youre wanting to tune from fuel trims just use the stock fuel trim histograms, but also make one that is LTFT+STFT in cutom math and use that as the "Z" axis instead of "STFT" or "LtFT"."

Could you elaborate more on that?

[horsepowerguru427]

"And yes, if youre wanting to tune from fuel trims just use the stock fuel trim histograms, but also make one that is LTFT+STFT in cutom math and use that as the "Z" axis instead of "STFT" or "LtFT"."

Could you elaborate more on that?

Sure, Open scanner, open log file, go to the histo area. Right click and go to Graphs layout. Then select the ST or LT fuel trim histo. Click "Clone graph" at the top of the top of the layout editor. Now use the 'clone' graph to make a new using LTFT+STFT histo. LTFT+STFT histogram MAF.jpg Hopefully these pictures help some. First is MAF and second is VE. LTFT+STFT histo VE.jpg This will give you an average of both fuel trims in histo form, so its usable in the tune.

Dont forget to add filtering in there as well. I just loaded a basic layout i had saved and alter when i need to use it, so it doesnt have filtering math in the function boxes yet.

[svl208]

So using LTFT + STFT (math) how do I build the graph?

What do I use for the column axis and row axis to calculate my error?

Thanks for the input.

[SiriusC1024]

Post #71 from that link I posted will show you all about it. Make the parameter LTFT+STFT.