Auto MAF (the begginning)

[kwhiteside]

So I've done my first AutoMAF log. The 2700-3300 range of the MAFFREQ/Ben Map kinda scare me.

Just to review my process first to make sure I'm doing it right.

b0120 set to 400 so I'm in PE mode all the time.
b3801 disabled, no LTFT
Logged MAFFReq in addition to my other PIDS
P0101 - p0103 set back to MIL
DFCO temp set real high to disable

Opened Log, then opened the B5001-MAF Calibration - LC1 WO2 BEN.map sample file. Change LC1 to my WO2AFR Ben and voila, my map filled in. See pic. I've also included my tun and log.

So I'm supposed to copy with labels, then paste and multiply with labels over the top of my B5001 right? What about those really high multipliers from 2700-3300?

What does the MAF Calibration LC1 WO2 AFR map do for you?

My car ran decent expect idle at stop got down to 500rpm. Makes you worry your gonna die out. That is probably another chapter later though.

Ken . . .

[mr.prick]

What does the MAF Calibration LC1 WO2 AFR map do for you?
It does the same thing that the VE WBO2 map did.

Despite what the the description tab for B5001 says,
after changing the VE table the MAF will need adjustment and
an across the board increase is not abnormal.
If you are going to enable LTFTs and changed B0101 with just WBO2
then don't waste your time with the MAF and WBO2.
FYI
B0120 sets the PCM to use the MAF sensor exclusively for airflow above it's value, not enable PE.

[5.7ute]

So I've done my first AutoMAF log. The 2700-3300 range of the MAFFREQ/Ben Map kinda scare me.

Just to review my process first to make sure I'm doing it right.

b0120 set to 400 so I'm in PE mode all the time.
b3801 disabled, no LTFT
Logged MAFFReq in addition to my other PIDS
P0101 - p0103 set back to MIL
DFCO temp set real high to disable

Opened Log, then opened the B5001-MAF Calibration - LC1 WO2 BEN.map sample file. Change LC1 to my WO2AFR Ben and voila, my map filled in. See pic. I've also included my tun and log.

So I'm supposed to copy with labels, then paste and multiply with labels over the top of my B5001 right? What about those really high multipliers from 2700-3300?

What does the MAF Calibration LC1 WO2 AFR map do for you?

My car ran decent expect idle at stop got down to 500rpm. Makes you worry your gonna die out. That is probably another chapter later though.

Ken . . .

Ken, did you set C2901/C2903 back to stock to reenable the maf?
Edit: just checked your tune & it was set back to stock. Doh

Also make sure you are filtering out the transients & low throttle positions etc. These are what will be giving you those high values from 2700-3300.

[kwhiteside]

What would be the filter to get rid of transients, TB > xxx % ?

I think I have DFCO enabled, set to come on above 86f. Is that right or wrong? I thought I set something to turn it off, but then I see this setting.

So much to learn, I thought the MAF was PE since it handled everthing over 4k rpm.

You know why I'm digging this stuff so much? Here it is.

I've been a programmer for my whole life. Building software and cogs that are challenging, but not nearly as satisfying as when I painted cars on the side. Everytime I handed over a car, it was quick satisfaction that was pinpointed to a brief period of action. Tuning seems to me to be a cross between the two. It's kind of like programming where you have to learn a lot of variables and manipulate them to get the results you want, but the thrill of driving you work, or a buddy driving your work, is like that painted car. The more difficult it is to achieve, the more pride you can take in the results.

Sorry for the rambling. I really appreciate all you guys helping out the newbies like myself.

[5.7ute]

I remove any data where TP is less than 1%. DFCO can stay turned on, just make sure you lift your foot straight off the throttle in Decel to allow the filter to remove this data. Slow steady acceleration will help to gather good data as well.

[kwhiteside]

Bare with me guys. I've been trying to get my mind around what is happening here. See the pic below. I went ahead and hardcoded the huge multipliers to 2, figuring if they need to really go higher, the next few runs will keep making that happen.

Correct me if I'm wrong here.

My wideband is reporting that during that ugly red range, I'm really pumping 3,4,5 times 14.67 into the engine (Extremely Lean). So by using the BEN multipliers to tweak my maf settings, I'll be telling (correcting) my MAF that for these ranges you are really pushing a lot more air than you think. AFter I make those changes, the net affect will be ( for the cells I hardcoded to 2x) half as much air, therefore a much richer mixture?

Oh, and just to make sure, 1500 MAFFREQ represents idle closed throttle and the bottom is full throttle?

One more thing. The fact that I have went from 78mm throttle body to a 90mm Tb, and also put a fast92 intake manifold should affect my maf how? It thinks the air passing thru it is being handled by the stock intake and a 78mm TB. Could this be why it is so far off?

[WeathermanShawn]

Ken, are you sure those MAF Frequencies you have highlighted are being filtered for DFCO?

I know you are keeping DFCO on while logging, but those values seem very odd. Just make sure when you filter, you filter out DFCO. You can filter it via throttle %, or better yet, any AFR over ~17.0 or spark advance of less than 10 degrees.

Your original columns are MAF Hz vs g/s. What are the second column values representing (chart on right)?

In calibrating my MAF, all my g/s calibrations increase for every Hz. I think it has to work that way.

[kwhiteside]

Ken, are you sure those MAF Frequencies you have highlighted are being filtered for DFCO?

I have the 6% TP Change filter applied



Maybe I missed it, but your original columns are MAF Hz vs g/s. What are the second column values representing (chart on right)?

The chart in the pic right above this post was using AFR instead of BEN, so when it reads 52, or 58, or 61, that is reported AFR :(

Now you will understand my concern with those ranges and bumping those numbers up as high as suggested. If you go up to my first post, you will see the suggested multipliers are 3.4 to 4 times. Nobody had chimed in, so I hardcoded to a max multiplier of 2 to be safe.

Now that I think about your comment of filtering out everything above 18, and reflecting on what happens to my AFR in my logs when I let off the gas, I think those values are from letting off the gas, and are very erroneous. My logs show my AFR going thru the roof every time I push in the clutch and let off the gas.

Any input would be great.

[joecar]

In your transient filter exclude TP less than 1% or 5% (i.e. closed throttle) and when driving/logging take your foot cleanly/smartly off the throttle pedal as 5.7ute said (might be easier if you disable DFCO during tuning since the PCM doesn't provide any real indication of DFCO active).

You will need to also filter out any AFR's greater than 15.00 say... and if you can log CPP (clutch pedal position, or whatever it's called) then filter out clutch disengagement too.

Your TB/intake may change MAF flow a little... so your MAF table may need a little adjustment... but only a little... 2x is too much.

(btw: the VE table is more meaningful when its units are g*K/kPa rather than %, but that's up to your preference).

[mr.prick]

If DFCO is on turn it off.
You may need more fuel in the VE table for that MAFFREQ range.

[kwhiteside]

Applied the AFR over 17 filter and that changed everything :)

I'm going to undo what I did and put that filter in.

I've had suggestions both ways as to DFCO, so unsure about that.

I'm looking in V8 BBL Pids and the only thing I see that could be clutch related is Transmision State, but I'm betting that is for Automatics anyway. That AFR over 17 did a real good job of getting rid of the clutch lean I think. When I hit the clutch, AFR goes 20+ instantly.

Joe, I saw you recommended 15 for the AFR filter. Isn't that a bit close to Stoich, could really be running a bit leaner than 15 in real world??? Either way, the filter brough all multipliers within 9.9 to 1.1, so now they are just tweaks!

DFCO yes, or DFCO no?

[WeathermanShawn]

Personally, I would disable DFCO when building a new tune. Manuals will hit that lean spike when shifting, with M6 DFCO Engaged. So to disengage, set M6 DFCO & DFCO temperature parameters to max.

You can also log the FTC Fuel Cells PIDS. You can learn a lot about fueling tracking those.

[mr.prick]

DFCO no.
Are'nt you racing, why use it?
DFCO cuts the injectors, and getting back on the throttle can give a slight hesitation.

Clutch operation can be logged with GM.STATE02
DFCO can be logged with GM.STATE05

Filters can be made for DFCO but like I said why use it?
How much fuel does DFCO really save?

[joecar]

DFCO in GM.STATE05 doesn't seem to work.

When tuning you don't really need DFCO ("How much fuel does DFCO really save?").

Yes, AFR 15.00 might be close, try then 16.00... 17.00 is fine too.

[5.7ute]

DFCO has never been a trouble to tune around if your filters are correct. Turning it off will just add a rich condition under hard decel & skew your readings the other way round. You could also add a filter removing MAP under 35kpa which will remove any data when DFCO is active.

[mr.prick]

I guess I should have tried it before suggesting it. :doh2:

[joecar]

Mick has a good point... it's better to make the filter exclude boundary conditions.

[mr.prick]

You will never get data in the areas that DFCO is active tho.
I have it off and I don't have rich decel issues. (anymore) :hihi:
IMO tune with it off and turn it back on later, but to each his own
Like I said "How much fuel does DFCO really save?"

[kwhiteside]

Ok guys, back on the road tomorrow.

When Checking DFCO, turns out I had the M6 temp to 286, but the other DFCO temp at 86. Maybe it was off anyways. Both at 286 now.

Settled on 16 AFR and above filter. When looking at my logs when my rpm dropped off the charts, my AFR was only going as high as 16.5 yo 17 most of the time.

Hooked up my Summit mechanical liquid fuel pressure gauge to the end of my fuel rail. Reads about 60 psi instead of the 70 my electronic one was reading, so I've verified I have stock injectors and standard stock pressure, 58 pounds as everyone reported. I guess I'll punch that into the spreadsheet to make sure my default IFR tables were set up right. I'm guessing they were right.

Looks like I've got the process going now. Slower accelleration, for good logs, filter off the high AFR's and the result will no doubt be minimal tweaks to the MAF. I'll get a few logs and flashes in over the rest of the week and move on. I'm guessing it will be time to consider LTFT's as I've heard it come up a bunch.

Ken . . .

[kwhiteside]

Made a log on the way in this morning. Not liking what I see. At low range, my maf is supposedly reporting low, but at high range it is reporting high. Now I can see it being off one way or the other, but at both ends does not compute. I moved the AFR filter in the example data below to 15.8. If I left it at 16 the lower cells pop up requesting even bigger changes. Closer I get to 15 with my afr filter, the lower end cells dissappear. Seems like a lot of cheating going on here and maybe the whole process isn't very scientific at all?

Feel free to flame away guys. I just want to trust what I'm doing a bit more.

I'll attach my log from the way in and my first iteration AutoMaf tune that it ran on.

[kwhiteside]

To add to it, I scanned my log and found that at idle, my Wideband AFR is almost always about .5 to .75 higher then the commanded 14.63.

Oh, before I started this, I pulled my LC1 out of the header and calibrated air calibrated it. During AutoVE we got it just about matching commanded too.

What do you guys think.
Could it be -
MAF really off, just keep tweaking it?
Leak?
Mods of bigger TB, Intake, Headers?

[WeathermanShawn]

When you complete 'AutoMAF' are you going back to closed-loop (using O2 sensors to maintain stoich), or open-loop?

Closed-Loop gets someone of a bad rap, but if you are getting close to where you want to be on your tune, enabling Trims will help 'clean-up' some of those problem areas.

On the DFCO debate, as always Mick has a great point about the 'Rich Decel' that can happen when you take your foot off the the throttle. I think however, for now you can work your current tune, but just be aware of the that the 'off-throttle' areas can be a challenge to tune.

[kwhiteside]

I want to puke. I just plugged in the stock z06 figures into the spreadsheet and found that my original tunes Injector Flow Rate table B4001 was not right.

My Injectors -
2001-2003 LS1/LS 24.7 (3 bar) 28.5 (4 bar)
part number 12561462
lbs-hr.@3 bar = (43.51 psi)
lbs-hr.@4 bar = (58.02 psi)

This means I have to start all over? Even redo my AutoVE work?

Pic below shows the difference.

[mr.prick]

If your injectors are stock, leave all the injector tables stock.
A Wahlbro 255lph will give you 60psi at idle but at WOT you will drop to 58psi,
if your battery voltage does not drop too much at WOT.
A tensioner helps to keep belt slippage down.

[kwhiteside]

I drove to work with my original b4001 table, drove home with the new one and reverted back to my first AutoMAF. The morning log had my AFR way off commanded, especially near idle. The log from the way home took that pukey feeling away as my AFR was surprisingly close to commanded. I'm going to apply tweaks to my B5001 MAF table from here. I'll know more tomorrow as I'll get two more log sessions in. I never thought I would enjoy my 45 minute commutes. Now I can't wait for those logging sessions. I suppose I'll have to go thru the VE again to get it right. That part has me perplexed because my AFR was following commanded real well by the end of my logging. I imagine I'm going to be running real rich when I go back to AutoVE mode with this new IFR b4001 table.

[5.7ute]

I drove to work with my original b4001 table, drove home with the new one and reverted back to my first AutoMAF. The morning log had my AFR way off commanded, especially near idle. The log from the way home took that pukey feeling away as my AFR was surprisingly close to commanded. I'm going to apply tweaks to my B5001 MAF table from here. I'll know more tomorrow as I'll get two more log sessions in. I never thought I would enjoy my 45 minute commutes. Now I can't wait for those logging sessions. I suppose I'll have to go thru the VE again to get it right. That part has me perplexed because my AFR was following commanded real well by the end of my logging. I imagine I'm going to be running real rich when I go back to AutoVE mode with this new IFR b4001 table.

If you scale the VE table by the same amount that you changed the IFR table everything will come back into line. For example, if you raised the IFR by 10% you need to raise the VE table by 10%.
Check out Marcins (Redhardsupras) blog for the indepth math on how this all works. He can explain it much better than I ever could.

[joecar]

+1 on what 5.7 said.

I calculated your spreadsheet IFR to be different by an average of -2.2% compare to your original IFR (please do check my math).

[kwhiteside]

I've already tweaked the table. I couldn't figure out how to get the % to do it right in the Scan tool, so I copied into excel and multiplied by .9777

Original kPa 0 value 3.6719 X .9777 = new value of 3.5910. Worked same for the other kPa's too.

Basically dropped all my my VE values just a tad, making everything a tad leaner. The lower IFR values in B4001 will cause the PCM to shoot a little more gas to achieve stoich.

I've got a couple more days of AutoMAF before I switch back to the AutoVE to validate that side of things.

Question for you guys. Before I started all this tuning, I took the car to a tuner for a tune. He basically said -

Ken, things are pretty far off on your car. I can't get AFR to follow commanded. I know you have EFILIVe and the wideband so it would be best if you tune it. Just to help you out Ken, I did back off the timing a bit so you don't fry anything at the track. So, my question is about that timing he backed out. How do I tune the timing back to optimial but safe? Please point me in the right direction.

[mr.prick]

In the Adjust: box type the value you want to add, negative numbers will subtract.
Adding a negative number is the same as subtracting.
To decrease you need - in front of the number

[joecar]

You could try the stock Z06 timing tables, this would be safe now because you know your AFR's are sufficiently rich... but keep an eye on KR and ECT, and make sure the AFR never goes lean when you're abusing your engine.

Your tuner was telling you that if he had to do it it would take a lot of time (multiply by hourly $ rate) and that you would be able to spend more cost-effective-time on it than he could... he is honest (he didn't just hack a tune into it and charge you $500).

Once you have the VE and MAF BEN's all sorted out, you could invest on a dyno session with your tuner to setup ignition timing and to fine tune the commanded AFR for best torque and power.