marthastewart

iTrader: (1)

Finished tuning OLSD and went back to CL MAF and now I am really confused. I thought my LTFT, STFT, and WB err would all be close to 0. Well their not!

My LTFT is like -13 for the majority of it, my STFT is close (from 0 to -6, and my WB 02 is a bit off about the same as STFT but not in the same area that the Fuel Trims are off at.

What one should I begin to tune, and get close to 0?

Pendragon

iTrader: (1)

Your going to have to start tuning your maf table now.

2000c-5

Reset your fuel trims when you go back to CL also.

marthastewart

iTrader: (1)

any tips or tricks on how to do that? I did reset my trims, they started at 0 and worked their way up.

2000c-5

For VE Tuning with a wideband,

You need to:

- set the Engine/Fuel Control/OL & CL/Closed Loop Closed Loop Enable/ECT vs IAT to 284* across the board. This will put you in open loop along with setting the MAF fail freq to 0.

- on the same page as above, you want to disable LTFT

- also on this same page, in Open Loop/EQ Ratio, set all cells to 1.00 for 140* and up (this will command 14.63 or stoich)
This step can be done several ways. You can leave it as is if you want to, or change the cells to 1.13 which will command 13.0 AFR, it doesn't really matter what you are commanding, because the % error will still be the same. Changing it to a set number makes it less confusing to look at the histogram later, since the AFRs won’t be changing due to coolant temperature changes. After tuning some people leave this table as is and some put it back to stock. It's your choice.


- In Engine/Fuel Control/Fuel Cutoff set DFCO enable temp to 284*

- in Engine/Fuel Control/COT, Lean Cruise set COT to disable

- in Eng. Diag/Airflow set MAF fail freq to 0 (you should also unplug the MAF if you can. If you are driving a 2001 and newer C-5 , the IAT is wired into the same plug, so you can’t unplug the MAF without doing some rewiring. They are seperate in the earlier C-5s)

- Now go log. Make sure you log VE for Actual AFR, Commanded AFR, and AFR Percent Error. I log first and then change the cell hits required to 25 for the % Error histogram.

- Right click/Copy the entire % Error histogram.

- Open Editor, highlight, right-click and use the “paste special/multiply by %” to the Engine/Airflow/General Airflow/Main VE/Primary table. As you get closer to 0, start using “paste special/multiply by –half”.

- Then, if you have a 1997-2000 C-5, copy the even numbered MAP lines to the secondary VE table by using the copy/paste method. Save and "write calibration only" to the PCM. Drive and see where you are.

Wash, Rinse, Repeat until your VE tables are in line. Your AFR % Error histograms should be as close to 0 as possible. It should only take 3-5 runs.

After this, it is time to tune MAF/WOT. Reset the MAF fail back to 14000 (leave everything else as is for now) and modify the MAF Calibration/Airflow vs. Frequency tables the same way you did for the VE tables, except you will use MAF vs Output Freq (Hz) histograms instead of the VE histograms. The MAF Calibration table is just above the VE table(s) on the same page in Editor.

After tuning MAF/WOT, set all of the above tables back normal and you’re done. Time to move on to spark, transmission settings or whatever you decide to do next. Have fun.

marthastewart

iTrader: (1)

Well I did have that printed out and followed it, other than the MAF Calibration. For some reason I though I was suppose to change the settings back so the fuel trims were active and then do that.

OK so where do I find the "MAF vs Output Freq (Hz) histograms "?

2000c-5

Nope, just remember that you don't use the fuel trims for tuning with a wideband. When you are done with the VE, MAF, and WOT tuning, you can use them to double check your work.

All the histograms are on your hard drive in the VCM Suite 2 folder, under "Histograms".

EDIT: Don't forget to log MAF (Hz) in the table display.

marthastewart

iTrader: (1)

Got all that and did it, Thanks!

Frost

iTrader: (45)

Do NOT zero the table (as you said yourself, logging commanded vs. actual yields real error) and you WILL be using that table in the future. You will use it every single time you start your car until it is in CL.

2000c-5

As long as you only change it above 140* it shouldn't affect any starting procedures. If it is over 14* outside, closed loop is enabled at 92* ECT.

The only other time you will be in Open Loop is in PE and it has it's own adder vs ECT.



EDIT: I see what you are talking about. It says change all or just the ones over 140*. I'll change that.

Frost

iTrader: (45)

All that aside, there really just isn't any reason to set it all to 1. Come up with a reason that shows neccesity; I can't think of a single one and it's one more table for those that are new to forget to put back afterwards.

If you think your car just jumps into closed loop at 92F above 14F IAT watch your scanner. All of your startup events have to expire and things have to be under control before it switches.

So really, list 1 GOOD reason to set that table to 1.

2000c-5

Just as good of a question is what is the problem if you do leave it set to 1? The stock OLFA tables are set to 12.9 (1.13 adder) AFR at MAP pressures 80 Kpa and above at normal operating temps. If you set your PE leaner than that (lots of LS1s are running 13.0, 13.1), it would still be 12.9 because the PCM will choose the richest of any tables when fueling. If you are new to the software, you aren't going to know why. The whole point of tuning is to have complete control over fueling, etc.

It makes things easier to read when looking at the histograms. It can be confusing to someone looking at their histogram for their Commanded for the first time and knowing it is supposed to be 14.7, yet the AFRs that show up in the histogram are all over the place because of coolant temps or throttle position, even though the % Error will still be the same regardless.

And because it coincides with what is in the HP Tuner Help files.