Calc.VET: correcting MAF and calculating VE (in single log)

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Originally Posted by COONDOG96

Hay Rich Z let me know if all the calc_pids.txt files work for you. I had this problem.

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Well, I'm using the .PDF tutorial, and looks like there is an error in the PID list provided. The PID that the tutorial calls for says "GM.DYNCYL_DMA" for "Air Flow Grams/Cyl-Speed Density", but the actual PID (as best I can tell) appears to actually be called "GM.DYNCYLAIR_DMA". It's this kind of stuff in a TUTORIAL that drives me insane. A tutorial, in my opinion, is supposed to teach someone about the topic matter. It really can't teach very well if it is inaccurate.

One thing that might be a real snag for me is that this procedure appears to use long term fuel trims. Yet my tuner told me he disabled LTFT in my tune, and at this point I don't have a clue about how to re-enable them. I've got all the mechanical issues now straightened out on my car (knock on wood) so I want to delve into this tuning stuff, but I've still got some questions I am having trouble finding answers to. The main thing is that my tuner is using a sloped IFR table in spite of the fact that my fuel pressure regulator is vacuum mapped. My car does run pretty good, even after his quickie tune to get me running, so I don't know if the guy just has some tricks up his sleeve that my inexperience can't even begin to understand, or if he did not realize the FPR is mapped. So far I haven't been able to get an answer out of him about it. But it's something I'm sure I need to know before I do anything in the tuning at all, as this is pretty much the base level to even begin to step up into the real tuning.

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Originally Posted by EagleMark

Open the Tune Tool and go to Edit, Configure Display Units and cahnge it to Metric instead of Imperial.

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Ah! Ok, that worked. Thanks for your help!

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One thing that might be a real snag for me is that this procedure appears to use long term fuel trims. Yet my tuner told me he disabled LTFT in my tune, and at this point I don't have a clue about how to re-enable them.

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CL or Closed Loop enable temp set to max temp disables LTFT.

Or {B3801} Long Term Fuel Trim Correction, set to eneable/disable.

What I haven't seen that would make Open Loop tuning easier then disconnecting O2 sensors and DTCs is STFT and LTFT min and max? Set these all to 128 and no fueling correction.

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Originally Posted by EagleMark

CL or Closed Loop enable temp set to max temp disables LTFT.

Or {B3801} Long Term Fuel Trim Correction, set to eneable/disable.

What I haven't seen that would make Open Loop tuning easier then disconnecting O2 sensors and DTCs is STFT and LTFT min and max? Set these all to 128 and no fueling correction.

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Ah, thanks. I can see where he used two methods to disable LTFT.

B3801 set to disable, and B3802 set to 284 degrees.

I can understand there being a minimum coolant temp to enable LTFT, but what does a MAXIMUM coolant temp enable really do? If the LTFT are already enabled at, say 180 degrees, what happens if you set a max of 230 degrees and the coolant temps HIT that? No sense in enabling LTFT again, is there?

BTW, what would be a good coolant temp to set for the enable? I noticed that my coolant temps are generally around 195 while driving.

Thanks for your help.

I was suggesting LTST/STFT fuel trims, not enable temps. Your tune has this in differant scale then what I posted. Mine has nothing.

But in your tune min temp allows LTFT to become active and max temp turns LTFT off, relying on STFT only. LTFT memory is not much help if your engine is overheating...

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Originally Posted by EagleMark

I was suggesting LTST/STFT fuel trims, not enable temps. Your tune has this in differant scale then what I posted. Mine has nothing.

But in your tune min temp allows LTFT to become active and max temp turns LTFT off, relying on STFT only. LTFT memory is not much help if your engine is overheating...

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OK, maybe I misunderstood what my tuner did. It appeared to me that he disabled B3801 AND also had the LTFT enable set to 284 degrees, which also effectively disabled LTFT. Does that sound right?

As for B3803, I guess it's just a terminology thing. To me I guess that would be the high temp that DISABLES LTFT, but it sounds more like negative logic saying that this is the MAXIMUM temperature that LTFT will be ENABLED. Of course, as you pointed out, if the engine is overheating what would disabling LTFT do anyway?

Thanks.

I'd have to test to be sure but either should turn off LTFT. Doing both was just safe.

If you look, one temp Enables when temps are coming up from cold, then there is a window of operation, then if it hits the upper/max it turns off.

OK. Well let me ask this: Do I actually NEED the LTFTs to be enabled for this CALC.VET procedure?

First paragraph in write up says...

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Calculate the entire VE Table from Idle to Redline RPM in a Single Log Session:

1. Tune Both Closed-Loop and PE Mode/WOT (simultaneously)
2. Calibrate MAF
3. Eliminate Trims

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Closed Loop is LTFT.

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Originally Posted by EagleMark

First paragraph in write up says...



Closed Loop is LTFT.

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Well, while logging my car, the status shows it is in closed loop, yet the LTFTs are not enabled. So what does that mean?