Could anyone give me any advice on what to do for tuning the spark tables for a 99 GMC Sierra. I have tried several different things and dont like the outcome of any of them.

Im not using a wideband, so its a little more difficult for me.

 

Any help on this guys. Theres nothing in hpt repository to look at

 

For a 99 you really need to switch to a 2002 OS.

For spark tables starting out i take the stock table and shift the entire table over 1 column for efi live for hpt you would shift it down 1 row. This will give you a decent gain of a few degrees. Also i smooth the table you dont want drastic jumps or dips.

 

Is that after Dialing the VE or before, or for stock is dialing the VE even needed

 

It is better to have your fuel set before you mess with timing, or you could just end up doing it all over again....

 

Honestly i do it before, but that is just me... Your not increasing that much to cause any damage...

I always dial in VE, but i use a wideband... Using Trims is not ideal because you counting on your O2 sensors being correct (Switch points)....

 

I get the fueling done first and then do the timing next.

If what you mean by not liking the outcome is that you are getting KR, I agree it's likely false knock due to the 99-00 Operating system. Switch to the 2002 OS will help and also, if you have an aftermarket cam/springs, you'll probably need to desensitize the knock sensors a bit too due to the extra valvetrain noise which could be detected as false kr.

 

If you dont adjust timing first you will just have to revisit your fueling after you adjust your timing.

This is what i do when i tune

1. Ve (wideband)
2. MAF (wideband)
3. Wot spark (Wideband monitoring)
4. Switch points (trims)
5. Fine tune MAF (trims)

 

Also while tuning the wot spark you also adjust the transient fueling

 

Arguments can be made for adjusting timing or fueling first. I'd rather be conservative with the timing at WOT prior to adjusting the fueling to avoid any detonation. Adjustments to fueling at WOT will need to be made regardless when fine tuning and doesn't take long at all. Ideally, the entire timing table would be tuned on dyno, but that just seems very time and cost prohibitive.