main ve and back up ve 99 ecm

[69camaro5speed]

i was doing a autotune on a 99 ta was trying to understand how the back up ve came in play i did it like the auto ve tutorial said dont understand how that works logging both ve tables and doing the auto tune on both how does the computer know witch one to use just trying not to run my self in circles any help would be great thanks

[69camaro5speed]

ok read some old post the back up ve is working when the maf is in defalt (doing the auto ve because the maf is off then ) and the main ve works when the maf is working so does that mean that both main and back up ve numbers need to be the same and same kpa i know there is more in the main ve but can still get the numbers closer allso this thing has a enormass cam would it be better to use maf to try smooth it out or just keep it in sd any in put would be great thanks

[foff667]

I always use the main ve map, correct that then paste it to the secondary.

[TAQuickness]

I always use the main ve map, correct that then paste it to the secondary.

I wouldn't recommend foff's suggestion.

On 99-00, the PCM uses the back up VE table in SD mode. The purpose of logging both is so you will have a properly calibrated VE tables for either SD or MAF mode.

[GMPX]

One of the reasons we never did custom O.S's for 1999 & 2000 Operating systems was because most people just upgrade the O.S to a 2001+ anyway, doing that also gets rid of the backup VE, plus the knock control in the early programs was not as nice.

Cheers,
Ross

[Doc]

I think all that foff was trying to say was just correct the main table first, then "copy with lables" to the backup or "secondary"- which will in effect update both tables. The burden of the older O/S will soon be over for me:D

[foff667]

correct...i just use a little converter for excel to do it...either way should technically work fine...i guess its up to the user in the end...not too long ago the way TAQNess was saying was shunned so its in the eyes of the beholder for the most part.