Ackattack1

iTrader: (7)

Hey guys, I'm fairly new to the whole tuning thing and am having some issues. This is on my 99 Vette with the mods that are in my sig.

Right now I'm working on kinda the first step, tuning the VE tables via the LTFT.

Here is what I've done.
Disabled the MAF by setting the Fail High frequency to 0, which then I get a check engine light.
Copied my High Octane table to the Low Octane
Essentially disabled PE by setting TPS position to 99%

So I then reset the LTFT, logged some numbers, drove a few more days logging some numbers. They're negatives. So then I "add" these negative numbers to my primary VE table (making the numbers in the Primary VE table smaller).

Then I drive a few more days, and log a few more times. Still negative numbers. So I "add" these negative numbers again.

I went through this a few times, and some of my numbers that were in the Primary VE table were negatives....so I set them at 1 (I actually think it would only go down to 0). And then I still get negative numbers.


So tonight I go back to an older tune, take my original logged numbers and add those to both the primary and secondary VE tables (again making them smaller) . I drive home (about 10 miles) and instantly my numbers are positive, some as +20.

So in all of the tuning instructions I've read, know one mentions using the Secondary VE table, but my car seems to be using them to do it's calculations while the MAF is tuned out.

Would I get different results if I actually unplug the MAF, should I just tune on the Secondary VE tables, Primary VE tables or what?

Also, after I change the VE tables, does the new tune affect the LTFT immediatly....cause I only reset the LTFT in the beginning.

Ackattack1

iTrader: (7)

Oh, I also went into my silverado tune and noticed that it doesn't have the secondary VE table, so I assume that is why nobody mentions it. Maybe it's a corvette specific table??

Ackattack1

iTrader: (7)

Well after doing some reading on HPtuners forum and here, I've answered my own question.
So here's what I found for other's reference.

Basically when you have a primary and secondary VE table, the computer uses the secondary VE table in speed density mode.

So, because of this, I used a log from earlier today (about 45 min of run time) to modify both the secondar and primary tables. I'll see how it works later. I'm going to keep the primary up to date with the secondary so once I'm done tuning the secondary table, the primary is also already done. I created an excel spreadsheet that is calculating both based on the LTFT and old VE tables. Hopefully it won't take too much to get them dialed in.

edcmat-l1

iTrader: (10)

You dont need to do a spread sheet. You can set up the histograms to do both the primary and back up VE.
Also, disable the long terms and just use the short term fuel trims to dial them in. Its much faster. You can get em both real close in a couple hours tops.