Tuning a 93 3.4 Firebird

[tkoforpresident]

what do we expect from GM??

[robertisaar]

did some looking, the VE values are generally similar in the 50-100kPa range, a little richer in the lower kPa cells in the idle tables... sounds like a way for the factory to save some time to me...

[tkoforpresident]

i meant larger #'s!!!

sorry.

[robertisaar]

larger numbers would be richer....

i'm going to do some investigating and comparisons...

[tkoforpresident]

without looking at a stock BIN in a while, i'm gonna guess that the idle VE is generally richer? that would GM's way of ensuring a good idle without needing to spend the time actually tuning it...

another thing: do you have the "Idle Fuel" Flag checked or unchecked? when it's checked, it goes off of IAC tables to determine BPW. you can tune the IAC tables but it's much easier to uncheck it and allow it to run off of the VE tables at idle.

yeah, your right about the idle tables they do seem generally richer (larger #'s) I'm not sure if i have the "Idle Fuel" flag checked or not so i'll go and look now. If it is checked i will uncheck it because i would rather it run off the VE tables so i don't have to tune the IAC table as well.

thanks for the info!

[robertisaar]

without looking at a stock BIN in a while, i'm gonna guess that the idle VE is generally richer? that would GM's way of ensuring a good idle without needing to spend the time actually tuning it...

another thing: do you have the "Idle Fuel" Flag checked or unchecked? when it's checked, it goes off of IAC tables to determine BPW. you can tune the IAC tables but it's much easier to uncheck it and allow it to run off of the VE tables at idle.

[tkoforpresident]

From what I gather if the Main table and the idle table have the same cell values, you copy over the correct adjusted value to both. IE: 600 RPM 12kpa cell in both Main and Idle, then they both get the same value........

Ok... I was getting confused because the VE values were different from one table to the next even in the same cell value. Robert said it was because GM was whack but i was thinking maybe it was because like you said idling at 1200 rpm and driving at 1200 rpm are different things and thefore that is why the VE values are different between the tables. (made sense to me)

but i'll just use one adjusted VE across the board as you are both suggesting.

Sorry for all the confusion, something wasn't clicking in my brain. I'm still new at this and am trying to make sense of whatever changes i am making.

[IsaacHayes]

From what I gather if the Main table and the idle table have the same cell values, you copy over the correct adjusted value to both. IE: 600 RPM 12kpa cell in both Main and Idle, then they both get the same value........

[tkoforpresident]

DF code... Not A1 code (A1 is what you are using right?). What does your idle table look like? RPM vs MAP? if so then it's the same style as DF. You're over thinking it...

I was saying, when you idle at say 1200 RPM, the MAP is a different value than when you put it in drive and idle at 1200 RPM. There is a load then, so different cells in the main/idle table will be active....

Anyway, just idle, idle in drive, drive around, data log etc and keep putting the adjusted stuff in until the BLM's are very close to 128 and you're done with VE... :P

yeah but should i replace all of the Idle VE data with the Main VE data??? Or should i come up with different data for them both??

[IsaacHayes]

DF code... Not A1 code (A1 is what you are using right?). What does your idle table look like? RPM vs MAP? if so then it's the same style as DF. You're over thinking it...

I was saying, when you idle at say 1200 RPM, the MAP is a different value than when you put it in drive and idle at 1200 RPM. There is a load then, so different cells in the main/idle table will be active....

Anyway, just idle, idle in drive, drive around, data log etc and keep putting the adjusted stuff in until the BLM's are very close to 128 and you're done with VE... :P

[tkoforpresident]

Yup, the idle table (at least in DF) is based on MAP values as well, so idling in neutral, or idling in drive will produce two different conditions and thus 2 different cells (or more) will need updating.

DF??

What are you saying? That the idle table values and main VE tables are going to be different for a reason because (for example) 1200 rpms in drive and 1200 rpms idling are different? If so, using the Main VE data in both tables won't work right?

[IsaacHayes]

Yup, the idle table (at least in DF) is based on MAP values as well, so idling in neutral, or idling in drive will produce two different conditions and thus 2 different cells (or more) will need updating.

[tkoforpresident]

well Isaac, if I am to follow the process of simply "replacing" the Idle table values with that of the main VE tables then technically the Idle tables will not be finished until the main VE tables are finished because sometimes the car sits at about 1400 rpm in drive and the idle VE table goes all the way up to 1600 rpm IIRC. So those values (from about 1200-1600) will be continuously changing along with the Main VE right?

[IsaacHayes]

You re-do them until they are as close to dead on as you can get them... Then it's tuned for VE.. Then you move on to spark/etc, and go back to VE if that changes after tuning spark/other things. If you mean that you've got Idle down, and will you have to adjust anything else, then the answer is yes. Idle is just idle.. driving is the main VE table where you get into higher RPMs, and different loads on the motor...

[robertisaar]

yes. it's a continual process, constantly refining until it's either perfect, or you call it good enough.