B0120 is set to 400 to restrict the source (airmass calculation) for LTFT-correction-to-MAF to be the MAF only (and not switching between MAF and VE).
B0120 is set to 400 to restrict the source (airmass calculation) for LTFT-correction-to-MAF to be the MAF only (and not switching between MAF and VE).
Sometimes it is quite difficult to know in a MAF-enabled car how much Trim function is coming from the VE Table and how much the MAF.
I did two log runs this morning. One with my regular VE Table, the other with a stock 2002 Camaro VE Table. I did reset the Trims prior to switching to the stock VE Table. I left B0120 at 4000 RPM's in each case.
By, the way I would never advised doing that. I could barely start the car (very rich). But, the CALC.VE % were virtually identical. CYLAIR.DMA and DYNCYLAIR.DMA were identical in run one, but very disproportionate in run two.
Trims were affected to some degree, but interestedly it still seemed like the MAF was doing the majority of the Trim function (except for idle). I did not make any MAF adjustments between runs. Is it possible that the VE Table makes an airflow correction fueling wise, but the actual LTFT function is controlled by the MAF?
Last edited by WeathermanShawn; February 10th, 2010 at 09:49 PM. Reason: revised
Hi Shawn,
Thank you for all you hard work and sharing you knowledge with us, as a private enthusiast and user of EFILive, I have really enjoyed reading and working through you concepts, with relative ease and success.
However I did pick up one problem, which I think I have resolved, but I thought I should check it with the forum to see if my thoughts are on the right path.
I set B0120 to 400rpm as the starting point, as I didn't want the VE table (was not calibrated and possibly out, since I have been fiddling from AUTO VE tutorial) influencing the MAF calibration. What I noticed though, was that you need to get the process done and then revert back to MAF 4000rpm as soon as possible. If I don't do this and drive around in traffic with MAF at 400RPM, the LTFL start to drift lean. I maybe incorrect in my assumption, but I felt this was due to, an increasing IAT and rapid throttle change (not entering PE, just normal pull off and gear change), with VE disable, the MAF had transient fuel problems causing lean, then rich every time I touched the throttle, because the MAF was delayed in picking up the sudden change. This caused the LTFT to compensate to lean. With out VE enabled, it seems to get worse as the day went on. Is this possible
Regards
Mark
I am leaning toward leaving the RPM Threshold at 4000 RPM.
That is a good observation. I think it might involve the B4106 LTFT Update Filter. Perhaps the LTFT's are using a Closed-loop mode determined from just the cylinder air input when using MAF. In any case, I am finding similar results. Even running my stock VE, the most that Trims were effected were +/- 2-6%. Not as much as I would have thought, given the huge difference in dynamic vs cylinder air in my tune.
Try keeping B0120 at 4000, and let me know how it goes.
Last edited by WeathermanShawn; February 10th, 2010 at 12:40 PM. Reason: Additional data..
I'm not a noob, but I am dumb, so spoonfeeding - bring it on. I'm encouraged by the relative simplicity of your approach, Shawn. I've never managed to get around to doing AutoVE.
The proof of the pudding is in the eating. If at the end of the day your AFR's are as commanded and your LTFT's are in order, you've gotten your airflow tables pretty close to correct. Good work and I look forward to your finalized tutorial.
Originally Posted by RevGTO
..Thats a good one.
Agree. Sometimes even I am surprised that some experienced tuners will not accept your last point. This method is not changing the laws of physics or engineering. It is more the technique of 'simplicity' that some confuse with inferior. In reality you could take any type of tuning and with the right choice of Calculated Pids, eliminate some redundant steps and make it easier.
Sometimes simpler is smarter. Thanks for your comments.
++1.
I disagree with this, here's why: WeathermanSean, WeathermanShaun, WeathermanShawn. There's only one right way to spell the man's [user]name, but if at the end of the day it sounds right, who cares?
Shawn - Yes, my offer still stands, just send me a PM or email when you're ready. I think you're onto something good here.
While you may not find Marcin to be the most charming individual you ever met, he is right.
Thanks TA:I disagree with this, here's why: WeathermanSean, WeathermanShaun, WeathermanShawn. There's only one right way to spell the man's [user]name, but if at the end of the day it sounds right, who cares?
Shawn - Yes, my offer still stands, just send me a PM or email when you're ready. I think you're onto something good here.
While you may not find Marcin to be the most charming individual you ever met, he is right.
I am used pretty used to my first name having multiple spellings.
Where I could certainly use the help is in the procedural steps (select, cut, paste, etc) that you did so well in your Tutorials. Quite frankly to this day no one has done it better. And unfortunately the AUTOVE method for SD Tuning has been unfairly pitted at times vs this technique. I have tried to be clear that my application is specific to MAF Closed-Loop.
I will accept your offer and PM you the material in the next week. At this point I am spending more hours to get that last 5% right, so your offer is not only very gracious but appreciated.
On your last point..well, tuning is still somewhat of a 'team sport', so perhaps you guys can help those whose intellectual skills outweigh their people skills.
I've heard all kinds of stuff about the AutoVE tutorial, good, bad, and ugly, none of it hurts my feelings.
I believe what RHS has been trying to say (Marcin correct me if I’m wrong), is that the tune is a system and must have accurate data throughout the calibration. The community as a whole focuses tuning effort on a select few tables, i.e. IFR, VE, and MAF, which completely ignores several pertinent factors in the tune. This in turn produces procedures and methods to tweak these three tables to compensate for bad calibration data, resulting in zero accurate data in a tune.
The argument, made by many towards Marcin, “if you know so much, why haven’t you produced anything?” is weak sauce.
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