Souless

iTrader: (2)

Ok, im trying to figure this out a little at a time. I have seen some people ask this question but no one seems to have a straight forward answer:

Little background:

Before cold start I let my WB warm up and then start the car and let it idle for about 2-5 minutes. When I am watching my WB i notice that it begins to go leaner and leaner. It starts at about 15AFR and then hits around 20AFR. After the car gets to about 160-180ECT it will being to richen up and sit around 15.0.

Now my question is, what tables affect this change during cold start, and which tables do I need to modify to richen the AFR during cold star?

I know it has to be a table in the "idle Airflow" section of HPT, but can someone explain these a little more. The IAC would have a big affect, but I dont quite understand the "Idle Airflow vs. coolant temp vs. (gear & pn)"

Frost

iTrader: (45)

Maybe after VE tuning you forgot and left your OLFA table at 1.0 across the board?

2002_Z28_Six_Speed

iTrader: (19)

IAC opening and closing shouldn't affect the AFR is you haven't played with the effective area tables and such.
not to that extent anyways

16floz470ml

iTrader: (2)

Just tune your olfa table with your wideband. Tune the table up to the point that you have closed loop enabled and leave that at 1.00.

jimmyblue

iTrader: (11)

Have you turned off the AIR pump to eliminate its
exhaust-oxygen "contribution"?

Souless

iTrader: (2)

Wait a sec, so what your telling me is that I should have set all the values under OL > EQ Ratio (HPTuners) to 1 before I started SD tuning??? Is that correct or am i missing something here? That would explain alot but I am just curious. I am posting my tune just to double check.
Thanks for the help guys now I am really curious.

edcmat-l1

iTrader: (10)

Sounds like your VE itself is a little lean.
A good check would be to turn off the fuel trims, either in your tune or using the scanner, and see what it does.

Frost

iTrader: (45)

the idea is, at operating temp (generally >160) you set it to 1 so that your commanded doesn't move around in OL.... this gets things accurate faster than trying to hit a moving target.

Your OLFA is one or less everywhere once warm in your file now... so you either lowered it like mad or you started with someone else's file and you didnt realize. Try putting OLFA back to something reasonable (stock and then remove maybe 10%-ish) .... with it being 1 all over like it is, you will have a period from just after start-up until you reach closed loop (or full regular operating temp if you are full-time OL) that will go lean. Remember we are in EQ and 1.0 is stoich. Greater is richer.

RedHardSupra

iTrader: (1)

no you shouldn't, it's an old myth that got propagated by people who dont understand where BEN/AFR%error comes from. it's a very common mistake, as i think it's in every single sticky/guide i've seen to date. off topic: wtf do we have moderators for?? need cleanup on isle five...

Frost

iTrader: (45)

It's not a myth; with sensor lag it's easier to get the VE nailed down with constant commanded fueling rather than having commanded wander all over the place. It's not like you can't put it back when you are done...

Gh0st

iTrader: (3)

From what I recall once you're at operating temps your OLFA is 1.0 anyways, at least on the 04 GTO it is.

Ben Diss

iTrader: (1)

It's the AFR error that matters when tuning VE. Leave the table alone.

kenp

iTrader: (9)

This issue of going very lean at cold start is one I noticed after my wideband install. At the time I was trying to work it out, my research showed that it is a common event. Some folks thought it might be related to cat lightoff and was burried in a table we did not have access to. IDK. I just don't let it bother me.