Basic CL/OL VE and MAF Tuning Steps

[ChrisV 02 - Z28]

Could a mod look this over and maybe make a sticky of some sort, if not no biggie

If anybody has any corrections or additions let me know so I can update my write-up
I have seen a lot of how to questions and as I was learning this myself I wrote this out for my use, and thought this might help others

Thanks!

UPDATED THE FILE

[AMERICAN_HP]

Rather than tuning with A/F ratio error, what about tuning based off of STFT??

I've been tuning everything to about 70kpa based off of my STFT. Then from 70kpa up, I tune based off of A/F ratio error (filtering out everything above 14.7) This allows me to only get data from WOT and dial in the upper regions even though i'm in PE..

Wadayathink?

[WS6FirebirdTA00]

why not tune off the WB, if you already have it in there, for the whole table?

[5_Liter_Eater]

CL/SD:

I'm not a fan of unplugging the MAF. Many vehicles have integrated IAT's in the MAF so it's not really an option. Just set the MAF Fail High Frequency to 0 and set the P0103 to MIL on first error and uncheck the SES Enable if you don't want to see the check engine light.

You need to mention that vehicles with secondary VE tables need to copy every other row from the primary VE to the secondary VE.

You need to mention to reset the fuel trims after each iteration.

I like to disable LTFTs and tune solely off of STFTs. It makes things much easier and quicker. Just my preference.

You could also get fancy with the histo and filter out any PE data by logging commanded AFR and using a filter of [SENS.121]>14.6.

OL/SD:

I have to agree that if you have a WB you should just tune with ARF Error. You don't need to worry about staying out of PE and can tune the entire VE table.

13:1 is the norm for NA but not FI.

CL/MAF:

Since you whacked the MAF PID in the VE tuning you need to mention to add it (in g/s and Hz) back again. This histo is not built in and you may want to add info on setting up the histos. Thats where a lot of people have problems. Maybe attach a config for each tuning method.

Again you need to mention resetting the trims in between runs.

I have not found it necessary to paste by 1/2 until you are within +- 2% or so.

[ChrisV 02 - Z28]

Thanks for the input 5LE, i will do some updates

[Cantalope Kid]

Okay okay...someone shoot me. I have done everything in CPIG's guide and honestly don't have a clue what tuning the MAF is or even where the MAF table is...I understand the LTFT and STFT adjustments to the VE, and KR* adjustments to the timing table...and some of the basics you list but WTF is this MAF table?

I will be using the following as my wideband is on back order.

CLOSED LOOP MAF (MAF TUNING w/ NARROW BAND)
1.Copy original tune (which now has ve tuned) to CLMAF.hpt
2.Copy high octane to low octane spark table
3.Engine-->Fuel Control-->Fuel Cutoff
DFCO Enable Normal Set enable temp to 284F (from stock -22)
4.Engine-->Fuel Control-->
a.Power Enrich-->EQ ratio vs. RPM set to your desired a/f across the board (1.13 = 13.0 afr)
b.Turn off COT
5.Engine-->Airflow-->Dynamic Airflow
High RPM Disable set to 500 (stock = 4000) this will set all airflow measurments over 500 rpm via MAF only, no VE table lookup
6.Use the average fuel trims from the histogram and Copy/Paste Special % Half
7.Might take several iterations to get your trims near 0%, try to get atleast within 2%
8.Once MAF table is adjusted copy it back to normal tune file to upload to car
9.If you have Wideband continue on to OPEN LOOP MAF

UPDATE: Just read some other threads you started. Looks like I am doing another LTFT+STFT and putting those adjustments into my MAF table just like the VE adjustments and then putting the stock=4000 back into play correct?

[Cantalope Kid]

When setting step 4.a P/E

What am I effectively telling the vehicle. Assumption - to hold a A/F ratio of 13.1 constantly or just when entering P/E? I get confused with commanded vs. X (they call its counter part.).

[Cantalope Kid]

Confusious here...Step 5

Why even go through the trouble of adjusting the VE table with STFT and LTFT if I am going to let the car rely on the MAF only over 500rpm from now on?

UPDATE: Just read some other threads you started. Looks like I am doing another LTFT+STFT and putting those adjustments into my MAF table just like the VE adjustments correct?

Also going to go do some RAF adjusting.

God I love walk thru's!

[5_Liter_Eater]

When setting step 4.a P/E

What am I effectively telling the vehicle. Assumption - to hold a A/F ratio of 13.1 constantly or just when entering P/E? I get confused with commanded vs. X (they call its counter part.).

Just to command 13:1 when you enter PE. All other times you will be commanding 14.7:1.

[5_Liter_Eater]

Confusious here...Step 5

Why even go through the trouble of adjusting the VE table with STFT and LTFT if I am going to let the car rely on the MAF only over 500rpm from now on?

You CAN leave the dyn airflow at 500 and reference only the MAF but I don't think thats what he had in mind. He has you set it like that so when tuning the MAF you know you are not referencing the VE. Just neglected to tell you to set it back to stock after you finish tuning the MAF.

[5_Liter_Eater]

Okay okay...someone shoot me. I have done everything in CPIG's guide and honestly don't have a clue what tuning the MAF is or even where the MAF table is...I understand the LTFT and STFT adjustments to the VE, and KR* adjustments to the timing table...and some of the basics you list but WTF is this MAF table?

Engine, Airflow, General Airflow, MAF Calibration. This table defines how much airflow the different frequencies equate to. It is independent of MAP and RPM which is why it's only one row. Very easy to tune. You just have to log MAF Hz and flow and set up a histo to plot the AFR Error (or fuel trims) against the MAF table.

[ChrisV 02 - Z28]

I added a revised version to the first post

[LinearX]

I've got to ask the dumb question.

Why would I go from CLSD to OLSD? Wouldn't it just be easier to pick one and tune with that method until you get the VE/MAF close, and then, if using narrowbands, go to a wideband for WOT?

[truckmann]

I've got to ask the dumb question.

Why would I go from CLSD to OLSD? Wouldn't it just be easier to pick one and tune with that method until you get the VE/MAF close, and then, if using narrowbands, go to a wideband for WOT?

You need to do all your tuning in OL or the VCM will be using the O2's to constantly try and keep your AFR at Stoich. So in effect with closed loop enabled you will never see the true fueling error of the tables you are trying to tune.

As far as SD goes it depends on what table you are tuning if you are tuning the VE table you don't want the MAF interfering, but if you are tuning the MAF you will need it on.

[LinearX]

You need to do all your tuning in OL or the VCM will be using the O2's to constantly try and keep your AFR at Stoich. So in effect with closed loop enabled you will never see the true fueling error of the tables you are trying to tune.

As far as SD goes it depends on what table you are tuning if you are tuning the VE table you don't want the MAF interfering, but if you are tuning the MAF you will need it on.

The reason I asked why go from CLSD to OLSD, is that the document in question has them in that order. Should one start in closed loop and then go to open loop, or just begin in open loop and be done with it?

[5_Liter_Eater]

It should be broken out differently IMO. If you have a WB there is little need to tune with fuel trims.

[LinearX]

It should be broken out differently IMO. If you have a WB there is little need to tune with fuel trims.

That's kind of what I was getting at. It made it sound like you should go from closed loop with the fuel trims to open loop with the wideband.

I would think pick one or the other and go until you reach the limit of needing the wideband for WOT.

Since I'm no tuning expert, though, I could be way off.

[ChrisV 02 - Z28]

The reason I put the CL then OL was for my case where my trims were somewhat aggressive while in cl, so I used closed loop just to get the trims closer to zero before i went to OL and keep my fueling from being way off. I agree you shouid either be in CL or in OL if you have wideband and stay with those methods that is just what i did to be safer with my fueling know it was quite off when starting

[LinearX]

The reason I put the CL then OL was for my case where my trims were somewhat aggressive while in cl, so I used closed loop just to get the trims closer to zero before i went to OL and keep my fueling from being way off. I agree you shouid either be in CL or in OL if you have wideband and stay with those methods that is just what i did to be safer with my fueling know it was quite off when starting

That makes more sense to me. Thus far, I've been doing everything in CLSD with STFT. Gotta get the dang LM-1 wicked up and configured so I can use it instead!

[ChrisV 02 - Z28]

Again sorry for the confusion on that, I wrote it at 2am on a work night
I tweaked it some and added a few notes to the end about that issue

Its not perfect but it will definately help you out in getting the modes setup