SladeX

Hopefully in future if anyone else does a search, they'll find this thread as when I search currently I'm not finding anything definitive.

I want to dial in the MAF on my car and I'm having issues with which parameters are needed for the default MAF error calculation. It seems like I've added in all the necessary parameters, but with a 24 byte limit, I'm maxed out and still can get that histogram to work.

I've got both MAF sensor, HZ, lb/min, A/F ratio commanded (high).

When I try to use the MAF - AFR Error histogram, it has PID Air Fuel Ratio Error and MAF Airflow vs output frequency for the X-header.

A/F Ratio Error does not work as a parameter for me, indicates unsupported or something and thus I've got no histogram to dial in MAF.

My second problem is that I want to work with a better MAF table to start with and my search found the Holden MAF tables, but they start much sooner in frequency than a 98 and last longer. The 98 starts at 1500 and is done by 11250. Is it safe to put in the values lined up for the holdern MAF starting at 1500? This is a concern as it starts at nearly double my current MAF values. If my maf is brought back into my tune, its affecting the LTFT as much as adding 15-19 compared to straight SD setup.

Please advise.

ZL1Killa

iTrader: (17)

for AF error to work you have to have an external wideband input into your datalogging.

just start with a stock MAF curve

SladeX

How does one correct MAF for partial throttle tuning? I have the AFR dialed in for SD, it was dyno tuned for the upper rpm just fine so I need to just get that bottom end dialed in for some in town fuel economy.

supergt99

iTrader: (1)

what mods do you have done to the car?

SladeX

Threw a rod on the bottom end so parts carried over from a gen3

6.2 L L92 block
-2.5 cc wiseco pistons
Patriot Performance 5.3L Stage 2.5 heads 62cc
LS6 intake
SLP lid
0.612/0.608 117LSA 230/230 duration Comp cam X-ER
QTP long tube headers with true duals and cats

I've got SD down to a T -1 to -3 across from 800-4000rpm at various part throttles.

I've "hacked" the MAF table and just mult % error until I got it to 1 to -1 in LTFT over a datalog. I don't feel like its a good way about going the MAF.


It's pretty smooth and no really hiccups save for what I think is the MAF ******* with my gas mileage basically saying ADD ADD ADD fuel when SD wise I'm bang on. I followed HP Tuner's web stickies for the SD dial in so I don't think I have a problem there, and prior to playing with the low end, the mid to upper end was tuned on a dyno.

ZL1Killa

iTrader: (17)

you say all this, and it sounds good. Have you verified stoich AFR at all part throttle conditions (NO PE,WOT..etc) and have you verified AFR WOT with a WIDEBAND?

it sounds like you are doing all this without a wideband... these things are one of those essential tools you know...

SladeX

the wideband tune was done earlier, its only part throttle that I'm dealing with now, the upper rpm was tuned on dyno with wideband from 3600 upward so I'm not touching things there.