txhorns281

iTrader: (12)

ok, where do I get MAF frequency values from though??? I'm sure I'd have to plug the MAF in for the computer to read that... but I'm just wondering where that data pops up, and if it doesn't how do I log it? Do i use the Mass air flow measured in Hz in the PID???

HumpinSS

iTrader: (1)

you plug the maf back up and force it into sd mode using the PO101 Delta talble. Then you log the MAF frequency Pid. I dont have the program in form of me but it is one of the maf pids

Black02SS

iTrader: (36)

This is a screen shot of what HumpinSS is refering to.

JimMueller

iTrader: (9)

What generated that image? Excel? Why the need for such huge cell height?

Black02SS

iTrader: (36)

EFI Live

txhorns281

iTrader: (12)

Ok do I change all the values in the P0101 Delta table to zero? I remember reading that you could set the MAF fail frequency to zero but I didn't ever find any verification that it actually put you in SD mode... anyone know?

HumpinSS

iTrader: (1)

Yes you change them all to 0 and this will force the car into SD mode (your ses light will also be on dont worry about it though)


Jim the is Efilives new software. It allows us to make custom histograms plotting any three sensors against each other

txhorns281

iTrader: (12)

OK guys, here's the final result! Download the MAFCalibration.cfg file so your scanner will be setup to observe the results! I layed my MAF table right over my dynamic airflow and I sure am impressed... Now my only question is this.... Why are my LTFTs still so negative around low rpm and idle??? I tuned out my table via Wideband, SD/Open Loop pretty dang close to 13.0 as WS6Snake-Eater's write up suggested... Then, I aligned my MAF table to my dyanmic airflow as you can see on the LOG file here...

*EDIT* apparently these files might not work on older versions of HPT... a buddy of mine just tried to view then and could not... I used v1.5

MAF Tune Config File for HP Tuners scanner (Right-click save as please!)
MAF Tune Log File (Right-click save as please!)

but check out the LTFTs in the histogram... I have a few ideas about what's going on here... but some seem inconsistent...

1) When i was tuning in SD/Open Loop i was targeting a 13.0 AFR, so my VE table is dead on when the VCM commands 13.0, but now that I'm back in closed loop and I'm commanding 14.628 so it seems natural that my motor will see me as running rich and subtract fuel... BUT if you look at the histogram my high MAP values the LTFTs are within normal swing... So if my whole table is tuned for 13.0 why wouldn't the whole table swing way off when trying to reach 14.628???

2) I did reset my fuel trims before logging but it seems that the LTFTs have somewhat already chosen which way they want to go... However the STFTs are still positive for now so the total corrections aren't to far of a swing... Does this mean anything???

3) Am I not waiting long enough for my fuel trims to learn themselves out??? I mean I drove for about 20 min, maybe 20 miles but like i said you can already kinda see where they wanna go sooooo I don't think there's too much room for improvement... And it is running richer cuz they gas smell is worse than before... pretty much as bad as before I started tuning...

Thoughts and comments always appreciated! (Almost there dammit... )

HumpinSS

iTrader: (1)

Sounds like you are back in closed loop. If your LTFT are learning you are in closed loop and when the pcm is in closed loop will try to acheive and maintain 14.7:1.


Kick it back into open loop and verify your AFR.

txhorns281

iTrader: (12)

I have verified my AFR already in open loop... and based on WS6SnakeEater's write up on the HPTuners forum, once the VE table is squared away you reactivate closed loop... So yes, I am in closed loop now and my trims are learning. IN open loop my car runs perfectly as commanded, but in closed loop it still runs at 14.7 because of trimming but my question is about the descrepancy between the open loop tuning and closed loop... If you tune the table to 13.0 in open loop, how will that possibly translate back to 14.7 in closed loop without wide swinging trims? I know we tune to 13.0 in open loop b/c it's a safe AFR, but is there something I'm missing here? if your VE table is tuned for 13.0, then of course it will swing when commanding 14.7, which would result in a "rich" motor.

Now I was thinking that it would be more accurate to tune the VE to 14.7 in open loop but that's not a safe AFR to be running at high rpms. Now i'm thinking maybe it's a sort of mix... maybe your VE should be tuned to 14.7 in lower rpms and 13.0 in higher rpms... PE mode will account for 4K and up anyway in closed loop and command richer AFR when the throttle threshold is met.... so beyond 4K my table is probably right where it should be because I will be commanding 13.0 in those rpms and it's tuned for 13.0. but below 4K it's tuned for 13.0 but wants 14.7... What stumps me is that why only idle and light throttle/low rpm (below 2K) are behaving like you would think... running rich and trims taking fuel out... In that same rpm range, but higher MAP it runs a tad lean... why wouldn't all rpms below PE mode (4K) be rich and need trims to take fuel out?

I've been thinking about this all night, and the only thing I can come up with is to tune low rpms, part throttle (not in PE mode) to 14.7 and transition or "roll" into 13.0 as you get to higher rpms, that way the VE table doesn't have a shelf right a 4K of going lean to rich... which would keep the VE smooth and make driveability good... right?

Bink

If your VE table is accurate at 13.0 commanded it should be accurate at the Factory F/A (Open Loop Stoich) settings. Put the table back to stock and the closed loop/ PCM ( MAF AIRMASS Calcs) should take care of the rest ( i.e. LTFTs). FWIW.

Another_User

Don't forget that your SD calculated airflow is more particular about air temperature and other factors than your MAF. I would imagine that it could give you a bad calculation, based on the weather. You are probably going to need to log under specific conditions.

txhorns281

iTrader: (12)

that's exactly what i did and this is the result... the Open Loop F/A table is not referenced after the car gets above 92 degrees... The VE should be accurate at any OL F/A table value since that's what I used to tune out my VE... I'm hope I don't sound rude, but am I being clear enough here?

I understand the concept of tuning the VE for one single commanded AFR... the idea behind doing this in open loop is that it takes out the trimming effect that way you deal directly with the VE and the AFR. In open loop though, since I have the PE Multiplier set to 1.00 in order to disable it, I can command 13.0 in the OL F/A table and even at 5K or 6K still verify my AFR, which I have done and completely tuned my whole VE table to produce a 13.0 AFR when commanded. Which means the VE in closely inline and will respond to any AFR I command it to in the OL F/A table.

Now when i re-enter stock OL F/A values I know that in open loop it will slowly transition from 14.7 to 13.0 strictly by MAP value, and with PE mode commanding 13.0, at WOT or over 4K (in my case) it will be safe to operate at high rpms and low MAP if that's ever the case... But the OL F/A has nothing to do with closed loop operation... To tell you the truth, now that I look at it I would rather not even be in closed loop because the OL F/A table seems to already have this "transition" in effect and there's no trimming to mess it up...

But the problem I'm trying to address is that in closed loop, the stoich AFR commander wants 14.7. So if you tune the VE (using the wideband method described in WS6SnakeEater's writeup) to a 13.0, when you reactivate closed loop mode, yes the trims will get you back to stoich 14.7, BUT I think they will have to work hard to do it... we're talking about a VE table that outputs 13.0 and the VCM wants to get that to 14.7... So in closed loop it HAS to take fuel out to do this but instead of using a multiplier it uses trims which leaves the actual VE table tuned at 13.0 always, but in realistically a well tuned motor would have the actual VE tuned at 14.7... that explains why I have a large negative swing in LTFTs as shown above... and large swinging LTFTs would mean that the motor (VE table) is not configured for stoich operation, thus the need for correction. And if I'm not mistaken, a motor that does not run close to stoich operation is NOT a well tuned motor right???

So the issue is how to get close to stoich in closed loop without significant trimming, I don't think it's possible without tuning your complete VE table out to 14.7, which can probably be done, but would be dangerous at higher RPMS... A VE that makes the VCM trim that much fuel from it is obviously not optimal. While trims do work for practical use, they only mask the inaccuracy of the VE table...

I'm not discrediting WS6SnakeEater's methods, but it does not seem consistent to just reactivate closed loop that commands 14.7 for a VE table that is tuned for 13.0... I think the OL F/A table's multiplier values that command AFR are more direct in configuring the VE as opposed to trims that recognize the inaccuracy of the VE through the o2s and then make adjustments..

Sorry to be so long winded but this is just something I stumbled upon and I'm looking for a sanity check here... Like I said, I'm not discrediting anyone but sometimes ya think you got it figured out when you don't... I'm hoping that maybe someone can hint as to why it behaves like so, based on the description I've given... I followed that writeup word for word and asked/learned alot in the process of using correct procedure and this is what I have, I've double and triple checked myself and I don't seen any holes... and if anyone agrees with this logic then I hope this helps those who didn't know any better...

txhorns281

iTrader: (12)

So then how do we compensate for this??? I did my logging and built my new MAF table, then relogged in the same afternoon about 3 hours apart...
Mass airflow does not have IAT incorporated to the function right? Whereas the SD dynamic A/F does? errrrrrrrrrg!!!!!!

txhorns281

iTrader: (12)

I'm thinking about going logging in open loop with my stock OL F/A table... hopefully this will provide some kind of insight...

WS6snake-eater

I think you are missing something somewhere, we just have to figure out what it is. 1st you do still have the MAF unplugged right? If so, I would like you to give this a shot if you have time:

disable closed loop and set the olfa table back to stock, also go ahead and disable DFCO...What this should do is place you in SD open loop tuning, however you will be running at the AFR commanded by the stock OLFA table as opposed to the 13.0. Take a good 20 minute drive and compare you WBo2 Histogram to the stock OLFA table. Do they follow the same trends? If so, then your VE is correct. I believe you are thinking a little too hard, and overcomplicating things. The VE table does not tune for one specific AFR, it is mearly a checksum reference that tells the computer how much air is in the cylinder at any given RPM/MAP point. Your OLFA table (open loop) and or stoich value/o2's (closed loop) then uses that checksum in it's calculation to determine your AFR.
If after driving you find that the WB is following the trend of the OLFA in the open loop config then you know that you have a problem somewhere in your closed loop settings, and not the VE. If you tuned your entire VE table to 13.0 AFR (WB verified) while the OLFA was set to 1.13, then your VE is correct.

Also did you ever look up the info on rescaling the VE boundries? That could also be causing you some problems. Another thought: I have seen you posting a bit about surging/bucking at low RPM's. In those threads you have mentioned making timing adjustments. Please be aware that drastic changes in timing can effect AFR. If you bumped your timing up a whole lot in the lower RPM's then it will show up leaner on the WB. More aggresive spark means more fuel is atomized and burned, thus resulting an a leaner condition.

txhorns281

iTrader: (12)

Hey Matt, thanks for the info! I will try that right now and report back! As far as the timing goes I did not ramp up timing very much at all, I only added 2 degrees down low and that was awhile back, I have been tuning with the same timing tables since I started your wideband method! Let's see if I can get some verification that my VE is right!

WS6snake-eater

Cool I probably won't be able to post back up until the morning, as I have practice tonight. But I look forward to seeing the results. If you can post a screen shot of your WBo2 histogram, and you OLFA table when completed, so that I can compare the two.

txhorns281

iTrader: (12)

Hey Matt... it looks like what i was thinkin wasn't the case... I'm glad you chimed in when you did because I was very confused... But this is interesting... take a look at these... I think I pinpointed the problem...

25 Min Open Loop/SD Mode Log commanding 13.0 on 1/10, ~70 degrees outside:



31 Min Today (1/13), Open Loop/SD Mode Log commanding stock OL F/A, ~50 degrees outside:





here's the stock OLFA AFR breakdown so you don't have to calc anything:



Ok so between these two logs the only difference was 20 degrees in outdoor temperature.... would weather really do this to a VE??? My log today (minus the extreme histogram values) was decently on commanded AFR but right where there was swinging trims in my closed loop log above, there are discrepancies in this Open loop log... I wonder where this will lead to... what to do what to do

WS6snake-eater

Looks like you have the table dialed in pretty damn good to me
The reason that I wanted you to do this, is because it creates a visual picture of what I was saying earlier about how the method does not have you tuning for a specific AFR but rather setting up an accurate base air table, for the computer to reference for fueling needs....Damn that was a long run on sentence...

Hopefully now you see what I mean. However we still have to figure out what the problem is with your tune. We know now that it is something in the closed loop configs, because the car is achieving the commanded AFR while in open loop. Go ahead and drop me a copy of your bin file to ws6snake_eater@hotmail.com and I will have a look at your closed loop params. Do you have LT headers? How old are your o2's?

Matt