WB Maf Tuning ... Questions/Logs

[Dirty Howie]

First of all thanks to all that helped me so far. I got my PLX up and running. And I am comfortable loging AFR % Error and adujusting the Maf Table. But I do have many questions and would appreciate you guys observing me as I go.

I basically will be logging once or twice a day....I have long drives to work.

Here goes with the questions:

1. Should I be OL with LTFT off or not?? If so do I need to place the car in OL and reset trims before each log.

2. I notice that my AFR Error is very high in the low frequencies and small in the higher (should I be doing some filters as in Bill's Demo.....)

3. After my second calibration my AFR at cruise seems to fluctuate well above stoich where before it was flutuating more evenly above and below stoich.

4. I reset my PE table to 1.13 per Russ but still see some low 12.XX AFR

5. Am I ready to use multiply %-1/2 yet

Included for you amusement is a pre WB tune and the latest calibrated tune plus the last two logs.

As always thanks for help and advise


DH

[12secSS]

Howie,

Here is my technique, it works for me very well and I can nail down my MAF tune in three sessions (two to tune, and one to verify prior to enabling MAF-CL).

1 - Set the vehicle to OL, disable DFCO, disable fuel trims, disable COT.
2 - Set OLFA = 1 and PE (for N/A) to 1.14 (12.8)
3 - log only Wideband, Commanded AFR, MAF hz
3a - if you have doubts about retard, either log Dynamic Air (G/cyl) and Retard. Or set your timing to the low octane. Either works
3b - Filters: I use at least 5 cell hits and decimal place of 2 (.xx)
4 - make a log while encountering as many "normal" (to you ) driving conditions as possible and a few WOT runs (4th preferrably from 3000-6000, or close to rev limit)
5 - copy the error % histogram values and paste special % to the MAF Table
6 - Now hand smooth the graph, referencing where the corrections were and were not made. Smooth those ares to the changed values, then smooth by hand any ares where you see unfavorable bumps.
7 - save and flash
8 - Go to step 3 until AFR error is about 1% or less. At this point you can get anal and start using the half percent and get the MAF Table (or VE) as smooth or correct as possible. Happy tuning!

[Dirty Howie]

George

Thanks very much for the detailed step by step

Couple of things using your list numbers:

1. I think I can find all those (havn't tried yet). COT disabled is not going to ruin my 02 sensors?

2. What does OLFA=1 do?? (hope I can find that one). Russ had recommended 13 AFR and you 12.8 ........ why the discrepency????

3. I assume you suggest just those 3 pid for best resolution?? I don't really get retard (twice so far).....but I get WOT pinging without KR. Russ,Bill and Doug were trying to help me with this before the recent WB install. What does the .xx decimal filter do??

4. Don't forget I have an A4 so I can give you 6K rpm in 3rd but I don't know about 4th........rev limit is set at 6800. At the track I hold 3rd to 135mph at 6400rpm if I remember

5. understood

6. I did do this but not sure exactly what you mean. I just went to the 2D graph and flatened out a coupl of resulting bumps from my previous smooth Maf curve.

7. understood

8. I am anal and have the WB permanently installed so I will get around to the minus 1/2 after I get down to 1% error. You mention VE ..... is it ok to ignore this now....it doesn't have to be done first like I keep reading about??

Thanks again and see next post toooooooooo

[Dirty Howie]

Well so much for my tuning abilities.......

I flashed the above file and got P0172 and P0175 (Rich condition Bank 1 and 2) soon after cold start. After some freeway driving I was able to clear the codes.

Looks like I better start over ...........

Here is the log....mostly freeway cruising with a little WOT blast at the end.


DH

[12secSS]

1. COT = Cat Over Temp protection. For those using cats, it will enrichen the fuel mixture as defined in the COT Setting, typically to around 11.7. The richer mixture helps keep your cat from "boiling over" during lean WOT runs. The reason why I disable it is because I like to target the least amount of commanded AFRs, much easier trying to hit two target rather then three ... especially when you don't know when they are going to kick in.

2. OLFA = Open Loop Fuel Air multiplier table, this goes back to targeting one commanded AFR. I like to run 12.8 for safety sake, plus it give better torque results. Others like running lean ("lean is mean" is what you will hear). Although some cars like running leaner then others, but that can be determined on a dyno.

3. Yes, it is for the best resolution and so you do not have to log as long to get as many hits as possible. Like someone once said "death by thousands of data points" ... or something like that. I am sure those guys will get you straightened out. It could be the knock sensor were over desensitized. As for the decimal places, I am anal and like to see all my data points in the same decimal equivalence (mechanical designer in me).

4. Oops, sorry! You are correct, it is 3rd in an A4. I am just used to dealing with a lot of M6'er. I am an A4 myself. You can also try 2nd if you do not want to upset the "neighborhood".

6. Precisely, you are doing good then.

8. You will want to have the VE dialed in first before the MAF, as the PCM sees both during throttle transitions (mainly the VE). So it is kind of crucial that those AFR are precise. Otherwise you may interpret a lean or rich VE condition as a MAF lean or rich condition.

Next Post:

You may want to verify the VE table by setting the MAF Fail mode to 0. You can leave the DTC codes alone or set them to NO MIL LIGHT. Do not set them to NO ERROR REPORTED, the car will run funky. With NO MIL LIGHT, it will just not illuminate the SES light, but will still trip the MAF DTC codes (as seen while logging). Again, for VE tuning I just log RPM, MAP, Wideband and AFR Commanded for best resolution.

[Dirty Howie]

1.
8. You will want to have the VE dialed in first before the MAF, as the PCM sees both during throttle transitions (mainly the VE). So it is kind of crucial that those AFR are precise. Otherwise you may interpret a lean or rich VE condition as a MAF lean or rich condition.

Next Post:

You may want to verify the VE table by setting the MAF Fail mode to 0. You can leave the DTC codes alone or set them to NO MIL LIGHT. Do not set them to NO ERROR REPORTED, the car will run funky. With NO MIL LIGHT, it will just not illuminate the SES light, but will still trip the MAF DTC codes (as seen while logging). Again, for VE tuning I just log RPM, MAP, Wideband and AFR Commanded for best resolution.

Well shucks !!!!!!! ...... I thought I wasn't going to have to go thru the VE tuning I need to look thru the help files as I'm unsure of what exactly to turn off and how to do it before proceeding. I'm not clear if setting open loop for instance is done by flashing a temporary tune or using the VCM controlls which I havn't tried yet.

Also.......I think I should flash the SD or Maf RTT as I have the credits burning a hole in my pocket. What do you think.....

On a positive note I updated my maf table with another new log and the rich codes did not come back!!!

[MMGT1]

Your an 8. VE is important to you...unlike the 6's
Glad that rich code is gone too! I'm just getting a handle on how the % "thingy" works for the special multiply(hahahaah)
I've been told by a solid source (Russ) to leave mine alone in the 6.

Are we having fun yet????????

[Dirty Howie]

Here is the log today without codes.

There is a little blast to 122mph at frame 3500. Seems like my %error is very low in the high frequency range as can be seen in chart and histogram.

But its way off in the low frequencies

[2000C-5]

Well shucks !!!!!!! ...... I thought I wasn't going to have to go thru the VE tuning I need to look thru the help files as I'm unsure of what exactly to turn off and how to do it before proceeding. I'm not clear if setting open loop for instance is done by flashing a temporary tune or using the VCM controlls which I havn't tried yet.

Also.......I think I should flash the SD or Maf RTT as I have the credits burning a hole in my pocket. What do you think.....

On a positive note I updated my maf table with another new log and the rich codes did not come back!!!

Howie, I am new to this too, but you definitely have to do the VE first. Worry about MAF later.

If you just set the MAF fail, you are in Closed Loop Speed Density and are still using the narrowbands.



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 to 1.00 or I just set the ones from 140* and up to 1.00 (this will command 14.63 or stoich)
This step can be done several ways too. You can leave it as is if you want or change it to 1.13 which will command 13.0 AFR, because it doesn't really matter what you are commanding, because the % error will still be the same. After going back to Closed Loop this table isn't used anymore.

- 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, but you won't be able to because your IAT is wired in the same plug, they are seperate in the earlier C-5s)

Now go log. Make sure you log VE for AFR, commanded AFR, and AFR percent error. I log first and then change the cell hits required to 25 for the percent error. Right click/Copy the percent error histogram, open Editor and use the paste special/multiply by % to the Engine/Airflow/General Airflow/Main VE/Primary table. Then, if you have a 1997-2000 C-5, copy the even numbered MAP lines to the secondary VE table by using the old copy/paste method. Save and "write calibration only" to the PCM. Drive and see where you are.

After this, reset the MAF fail back to 14000 (leave everything else as is for now) and do the same thing for the MAF tables using MAF vs Output Freq (Hz) histograms instead of the VE histograms.


Someone please correct me if any of this is wrong or misleading.

EDIT: OK, I have been corrected. The common consensus is to leave PE enabled because the first time you go WOT you don't know what your AFR is going to be. If you have done a lot of mods, chances are it will be lean. Sure, you can change it for the next run, but what damage was done already if it was too lean?

I am going to edit the information above to reflect this so if anyone wants to copy it as a guide it will be correct.

[Dirty Howie]

Howie, I am new to this too, but you definitely have to do the VE first. Worry about MAF later.

If you just set the MAF fail, you are in Closed Loop Speed Density and are still using the narrowbands.

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 to 1.00 or I just set the ones from 140* and up to 1.00 (this will command 14.63 or stoich)

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

- in Engine/Fuel Control/Power Enrich set PE Enable/MAP to 640

- in Engine/Fuel Control/COT, Lean Cruise set COT to disable (this won't hurt the O2s, but could damage the cats if you still have them)

- in Eng. Diag/Airflow set MAF fail freq to 0 (you should also unplug the MAF if you can, but you won't be able to because your IAT is wired in the same plug, they are seperate in the earlier C-5s)

Now go log. Make sure you log VE for AFR, commanded AFR, and AFR percent error. I log first and then change the cell hits required to 25 for the percent error. Right click/Copy the percent error histogram, open Editor and use the paste special/multiply by % to the Engine/Airflow/General Airflow/Main VE/Primary table. Then, copy the even numbered MAP lines to the secondary table by using the old copy/paste method. Save and "write calibration only" to the PCM. Drive and see where you are. It only took me about 3 tries to get mine spot on.

After this, reset the MAF fail back to 14000 (leave everything else as is for now) and do the same thing for the MAF tables using MAF vs Output Freq (Hz) histograms instead of the VE histograms.


Someone please correct me if any of this is wrong or misleading.

You seem to have the basics very good for a noobie

Appreciate the necessary settings and their locations!!!!

So you set these variables in the editor for the tune you are working on.....and flash it. Do the logs.....transfer the histograms. And flash again. For some reason I thought the VCM Controll had to be used.

I do have cats...but they are highflow that came with the Kooks headers. I hope I don't burn them up......how likey is this do you think??


DH

[2000C-5]

You seem to have the basics very good for a noobie

Appreciate the necessary settings and their locations!!!!
DH

Thanks, it took hours and hours of reading on here and other places. I tried doing it without a wideband at first, because I didn't know any better. Using a wideband absolutely takes a lot of the headache out of it.

I logged stuff for weeks, and used tank after tank of fuel at the beginning. I got my wideband, and started over with VE and was done in less than two days, and that was taking my time. Also, used less than half a tank of gas.

So you set these variables in the editor for the tune you are working on.....and flash it. Do the logs.....transfer the histograms. And flash again. For some reason I thought the VCM Controll had to be used.
DH

Correct, just set those variables in the tune you are now using. When you save it you can hit Save File or go to File/Save As and save/rename it as a different file, so you have your original as a backup. No VCM controls needed unless you don't like looking at the check engine light.

Yea...log....copy....paste special....flash.

Wash...rinse....repeat. It's amazing how fast it gets in line. It shouldn't take you more than 4-5 runs for each one.

I have a post in the Gen 3 section asking some questions about logging MAF and WOT, so when you get your VE in line, check it out and it should answer some of the questions you may have then.

[2000C-5]

One more thing, I see you are using the EIO for logging. While you are setting the basics (VE, MAF, WOT) it is a lot easier to use a laptop so that you can actually see the cells you are hitting. That way you can adjust speed/throttle position (with your foot ) to hit as many cells, as many times as possible.

I'm using the SM-AFR also, using it as a narrowband/wideband. It is flawless so far. I got the gauge with mine, so when I'm not logging I have a reference.

[Dirty Howie]

One more thing, I see you are using the EIO for logging. While you are setting the basics (VE, MAF, WOT) it is a lot easier to use a laptop so that you can actually see the cells you are hitting. That way you can adjust speed/throttle position (with your foot ) to hit as many cells, as many times as possible.

I'm using the SM-AFR also, using it as a narrowband/wideband. It is flawless so far. I got the gauge with mine, so when I'm not logging I have a reference.

Congrats on setting up the SM-AFR as dual sensor!!!!!! I originally wanted to do this but was convinced it was much simpler to go separate WB bung. I liked the idea of having one less 02 sensor to burn up ..... I have gone thru 2-3 of them.

Anyways, I know to use histogram #8 for WB AFR % error and copy to MAF frequency table. But which histogram do you use for the VE table ???

And what is this all about...."Then, copy the even numbered MAP lines to the secondary table by using the old copy/paste method."

Did you upgrade to the 1Bar SD/RRT ??? I forgot what this does to help in tunning besides the RTT.....which I am NOT ready for!!!!

BTW: I really like my computer and really drive my car.......so the computer is staying at home. I rather do some longer logs

Thanks,


DH

[MMGT1]

#6= Wideband AFR----------will show actual AFR in all MAP vs RPM(X by Y Chart)
#7= VE AFR Error%----------Will show errror in Volumetric Effency(X by Y chart)
#8= MAF Error, AFR Error%---Will show error in the linear MAF scale

[12secSS]

Howie,

You are a 2004, you do not have a secondary VE table like 2000 and previous models. Since 2001, GM eliminated the secondary VE table.

Also, I would not set the PE Enable/MAP to 640. I would keep it set to stock, this way you can correct the PE AFR as well, plus you will not run the risk of boiling your cats with the 14.7 AFR. Otherwise everything that 2000C-5 has posted is correct, and inline with what I also posted.

[5_Liter_Eater]

Thats the beauty of WB tuning. It doesn't matter if you're in PE or not. All you cvare about is the % AFR Error from commanded. No more fuel trims for you Howie.

[Dirty Howie]

#6= Wideband AFR----------will show actual AFR in all MAP vs RPM(X by Y Chart)
#7= VE AFR Error%----------Will show errror in Volumetric Effency(X by Y chart)
#8= MAF Error, AFR Error%---Will show error in the linear MAF scale

So I use #7 ....right ???


DH

[Dirty Howie]

Howie,

You are a 2004, you do not have a secondary VE table like 2000 and previous models. Since 2001, GM eliminated the secondary VE table.

Also, I would not set the PE Enable/MAP to 640. I would keep it set to stock, this way you can correct the PE AFR as well, plus you will not run the risk of boiling your cats with the 14.7 AFR. Otherwise everything that 2000C-5 has posted is correct, and inline with what I also posted.

I will have to check my tune ...... I assume the PE Enable/Map is stock. I like the idea of not risking damage to the cats.

Thanks for confirming 2000c-5 outline. I got to check it out and start doing it!!!!!!! I'm comfortable with the Maf tuning now but need to look at the VE stuff and make sure I am using the correct histogram for changes (#7??)


DH

[Dirty Howie]

Thats the beauty of WB tuning. It doesn't matter if you're in PE or not. All you cvare about is the % AFR Error from commanded. No more fuel trims for you Howie.

Bill

I think part of my confusion is that I read too much about stft/ltft and cells/ve (although never trying it out) that now that I got the WB I wasn't clear where to start


DH

[2000C-5]

Congrats on setting up the SM-AFR as dual sensor!!!!!! I originally wanted to do this but was convinced it was much simpler to go separate WB bung. I liked the idea of having one less 02 sensor to burn up ..... I have gone thru 2-3 of them.

Anyways, I know to use histogram #8 for WB AFR % error and copy to MAF frequency table. But which histogram do you use for the VE table ???

And what is this all about...."Then, copy the even numbered MAP lines to the secondary table by using the old copy/paste method."

Did you upgrade to the 1Bar SD/RRT ??? I forgot what this does to help in tunning besides the RTT.....which I am NOT ready for!!!!


Thanks,


DH

Yea, oops...I forgot you don't have the secondary VE tables.

BTW: I really like my computer and really drive my car.......so the computer is staying at home. I rather do some longer logs

DH

I didn't mean to take it to the track with you. When you start logging the VE tables you'll see what I mean. It's not like logging for MAF freq.

Howie,


Also, I would not set the PE Enable/MAP to 640. I would keep it set to stock, this way you can correct the PE AFR as well, plus you will not run the risk of boiling your cats with the 14.7 AFR. Otherwise everything that 2000C-5 has posted is correct, and inline with what I also posted.

This is the question I asked in the other post. It seems the common consensus is to leave PE enabled. I am going to change that in the post above, so if anyone wants to copy it, it will be correct. I see why also, because the first time you go WOT, you don't know what kind of AFR you are going to have. If it happens to be way lean, sure you can correct it for the next run, but what damage did you do in the meantime?

So I use #7 ....right ???


DH

Right.