MAF airflow learning control

[VX L67 Getrag]

Seeing with MAF's you need to get the G/s rate correct for car's to idle correctly with major airflow change components I've been doing a bit of testing!

As you need to get the flow delta table right for primary correction I thought of making up a history table as it's laid out.
The only thing that i'm not 100% sure on if I choose VSS or roadspeed as the Column X(axis).
I tell it zero for P/n then just chose 15(first gear) 30(2nd gear) 45(3rd gear) 60(4th gear) & 75(5th gear-if applicable).
I then have the Row Y(axis) setup as the RPM in same format as gear delta table (17 lines from 400 to 2000).
But when looking at the data thats being set there it's a lot higher than in the delta table, so there must be other modifiers being brought into it?

If we knew what each of the modifiers to add in it would make for a perfect learnt airflow table & no stalling & re-jigging other scalars?

Another thing we would then need to know is when it's being logged as Idle Flow Control, or speed flow control.. is there a flag for this to know what it's in?

It does seem in the logged data from history table I made up the idle area G/s does line up 100% with initial value for learned airflow with A/con on or off settings!

[antus]

It should be more simple than that. Log hz vs (wideband afr divided by target afr) and set the hz to the same labels in your histogram as whats in the maf tables. Then you should be able to multiple the existing gm by the histogram results. All the other modifiers come in to play before you get the target afr value, so all you should be concerned with is how far out the actual AFR is. This is assuming a tuned car that was running correctly where the only change is the maf which then needs to be remapped.

So say at 5khz, the wideband is reporting 13.0 and the target afr is 14.7 then 13/14.7=0.884 so at 5khz if your existing maf table says 20gms/s multiply 20*0.884 and your new value is 17.6 grams. (less metered air at that hz will mean the car injects less fuel which will lean your 13.0 out a bit and should give you your target of 14.7).

Have I miss understood what your trying to achieve?

[VX L67 Getrag]

No Antus,

This is a different thing entirely...

it's not for fuelling it for air control, idling issues!

But yeah fuelling is exactly as you mentioned a lot easier & there is already history tables & excel sheets made up for that!

[The1]

just be aware that fiddling with the MAF tables in that way will make it no longer linear, the MAF will obviously report different readings in different conditions and temperatures, if it is linear it can then linearly compensate, this is why it's much much easier to adjust the base injector rate to bring your overall injector multiplier table back into range. But each to his own, im watching this thread to see if someone can make another workable solution.

[VX L67 Getrag]

NO I'M NOT FIDDLING WITH THE MAF TABLES!!!!

It's the learned air flow delta for park/neutral, 1st gear, 2nd gear, 3rd gear, 4th gear (5th if applicable).

am I wording this wrong I'm not talking Hz I'm talking g/s in the flow delta table!

[VX L67 Getrag]

I'm not 100% but just looking through the data stream the bit mask for whether it's rolling or stationary may be called;
PID idle control is enabled? does that sound right?

[The1]

ah i see you meant the Idle Airflow Learning tables for each gear?

It's used to calculate a Airflow variable, the variable is used in Decel AFR Calculations, Throttle Follower Logic and IAC Error Control

To redo the table should be simple, make another history table just like the table itself, using rpm and current gear, then plot a log back of G/S from MAF.

[VX L67 Getrag]

Yeah but if you do that, you'll see the figures that get logged are nearly 3 times higher than what's in that table!

So there has to be other modifiers coming into play, would also be handy to know what the flag is to log when it's in moving idle flow control & stationary idle flow control!

[The1]

yes that's right as it's no longer stock, if you log a full stock setup it is pretty close!

[The1]

here's a bit of log from a full stock vs v6, then my vs v6 with card maf.

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