AFR fluctuations on throttle transistions in SD

[0rion]

I have my ve looking pretty good but the car does something that's driving me crazy and I don't have a clue where to look to fix it. Anytime I open the throttle the AFR will go a little lean for a second or two and anytime I close the blade it will go a little rich for a second or two. Can someone point me to where I should look to fix that? It also does this when it goes to PE, there's a delay before the AFR drops to PE commanded and when coming out of PE there's a delay before it returns to stoich. Thanks in advance for any ideas on where to start looking. My current tune and logs are on the laptop. I'll transfer them to my desktop tomorrow but I don't really want someone to fix it for me. I'd just like to know where to start looking.

[mowton]

Enrichment Rate in the Power Enrichment Table looks like a good candidate. I have never messed with it yet but it is set to 1.0 for my modified C5 Corvette. Sets the delay in reaching the final PE value...0 to 4 with the lower the number, the slower to reach PE Equivalance value. Not sure about going the other way.

[0rion]

wouldn't that only come into effect when going to PE though? It also does it under cruise conditions. I'm curious to see what it does when I go back to CLMAF.

[TiredGXP]

Anytime I open the throttle the AFR will go a little lean for a second or two and anytime I close the blade it will go a little rich for a second or two. Can someone point me to where I should look to fix that?

I figure it's got to be something to do with transient fueling.

According to the HPT help file:

During positive throttle (MAP) transients additional fuel must be injected than commanded to account for the fact that not all the fuel injected will make it into the cylinder. If additional fuel were not injected a lean condition would result as more fuel is puddling on the valve and port walls rather than entering the cylinder.

Conversely, during negative throttle (MAP) transients, less fuel needs to be injected than commanded to account for remaining fuel that is still boiling off the walls. If less fuel was not injected a rich condition would result.

I'm not sure how to adjust transient fueling and just live with the short bursts of lean/rich on throttle changes (usually only lasts a few frames on the log).

[WS6FirebirdTA00]

what injectors?

[jimmyblue]

There is also a filtering that is done on the VE table values as
you travers the surface, and if you have a motor where big
changes happen (VE vs MAP especially) the filter value will
make the airflow readings lag actual airflow, more or less. Has
anyone played with this filter and seen improvement in speed
density transient fueling accuracy? All I see is some cautions
that too much reduction will make it unstable.

[svede1212]

no but i've wondered about that too. i guess it needs at least a bit of an average to work properly. i don't think those little bits of lag are a big deal but it would be interesting if someone tried it. you do it first