maf adjustments

[smslyguy]

Can you adjust the maf feq table by using the wideband ben's the same way you would adjust the v.e table? (by copy and past with labels)? I have already got my v.e table good (or close to it) but while scanning with my w.b. bens for the maf adjustments it show they are off. My L.T.F.T. are within reason as well. Here is a copy of my scan.

[joecar]

Yes, but first set B0120 to 400 rpm or less (and also stay in OL).

[smslyguy]

ok thanks, but what is the reason for staying in o.L vrs c.l

[joecar]

CL will trim to stoich (i.e. LTFT applies its correction) which cause the wideband ben to be at 1.00 (i.e. no wideband ben correction).

AutoMAF objective is to isolate airmass source to the MAF, and to watch the resulting AFR...
if CL is enabled the resulting AFR is being manipulated while the wideband is watching it.

For example, say MAF is providing low airmass, so fuelmass will be low, LTFT applies say +10% to bring AFR to stoich (commanded AFR in CL)... wideband sees stoich AFR, so wideband ben is 1.00 (i.e. no correction to MAF table)... you would either have to manually apply the LTFT to the MAF while in CL, or disable CL and apply the wideband ben to the MAF (must filter transients in either case).

See WeathermanShawns tutorial for MAF correction from LTFT and VE calculation from MAF airflow.

[smslyguy]

CL will trim to stoich (i.e. LTFT applies its correction) which cause the wideband ben to be at 1.00 (i.e. no wideband ben correction).

AutoMAF objective is to isolate airmass source to the MAF, and to watch the resulting AFR...
if CL is enabled the resulting AFR is being manipulated while the wideband is watching it.

For example, say MAF is providing low airmass, so fuelmass will be low, LTFT applies say +10% to bring AFR to stoich (commanded AFR in CL)... wideband sees stoich AFR, so wideband ben is 1.00 (i.e. no correction to MAF table)... you would either have to manually apply the LTFT to the MAF while in CL, or disable CL and apply the wideband ben to the MAF (must filter transients in either case).

See WeathermanShawns tutorial for MAF correction from LTFT and VE calculation from MAF airflow.

thanks joecar for the info. makes sense, but why do the ben's in the scan from above while running in c.l. have higher than 1 if the trims were working, which they were wouldn't it be a steady 1 then at stoich?

[joecar]

In your log file from post #1 the ben's are right on 1.00...

Do you mean those lean spikes on decel/closed throttle...?
Those lean spikes are either DFCO enabling (the wideband sees free air).

Those lean spikes should be filtered out before applying ben map to either of VE or MAF tables.