Question regarding the Sticky: Calculating MAF Airflow From VE Table..CALC VET In Rev

[tor1965]

I don’t understand this “Sticky:Calculating MAF Airflow From VE Table..CALC VET. In Reverse”.

The first thing to do is to disable MAF. And go in speed density “mode”, (I can chose to run open ore close loop)
This means that I can use WBO2 ben or LTFT ben to adjust the ve table without the influence of the MAF
So far so good.

But then I am reading this sentence:
“Calculate the entire MAF/VE Table from Idle to Redline RPM in a Single Log Session:”

In one log session with MAF disabled? How can this be true?

I am logging “VE table lookup value” that is giving me the readings from the ve table in the tun, and I suppose it is then ben corrected in the CALC.MAFT or uncorrected in the CALC.MAFN
My question is then. How can I use this value?
The point here (as i understand it) is to correct the MAF table with the data from the ve table in the tun.
The sticky says in one logging session and with the MAF disabled?
When the MAF is disabled my GM.MAFFREQ are reading zero. I don’t understand how to populate the MAF table as long as the maf is disabled.

If I first log and correct the VE table. Then enable the MAF, make a new log and use VE table lookup value to calculate the correct MAF readings then I can understand. But this is not in “One logging session” Is there something I miss her?

[joecar]

It calculates the MAF table from the corrected existing VE table (look at the calc pid for CALC.MAFN and CALC.MAFT).

You paste CALC.MAFT into the MAF table B5001, and you paste-multiply CALC.SELBEN into the VE table B0101.

The point is to calculate the MAF and to correct the VE table, simultaneously (i.e. in one log).

MAF sensor should still be present, but it should be failed via the MAF diagnostics sanity tables (which triggers a DTC), so it will still produce MAFFREQ but the PCM ignores the MAF data (when the DTC is present). If you physically remove the MAF then MAFFREQ will be zero.

[joecar]

Calc.VET tutorial: correct MAF, calculate VE from corrected MAF.
Calc.MAFT tutorial: correct VE, calculate MAF from corrected VE.

In both cases, the correction is provided by the multiplier CALC.SELBEN.

[joecar]

If you don't care for the MAF, you can physically remove it, this will then simply give you a corrected VE.

[tor1965]

Hi Joecar
So when it says “1. Disable MAF:” it means by the tun, not to physically unplug it.
That makes sense.

Is it code P0101 that confirm that the maf is correctly disabled?

Thanks

Tor

[joecar]

Yes, MAF disabled via tune.

Yes, P0101, or P0102 or P0103.