Novice tuner needs help


Active Member
Dec 18, 2009
:confused: Is it possible to be lean and not have any knock?I am running a stock turbo,stock intercooler with Dutt neck, 42lbs injectors and a TT street chip running 93oct fuel with 18lbs boost.Fuel pressure was 43lbs line off added 13% more fuel in the chip.Made some 3rd gear pulls and this is where my o2's fell:
1)757-0 knock
no changes made
2)750-0 knock
added fuel from 13% to 18% in the chip
3)781-0 knock
no changes made
4)789-0 knock
added a little more fuel to get it in the 790's,from 18% to 18.8%
5)781-0 knock
no changes made
6)777-0 knock
Confused that when I added a little more fuel between run 4 and run 6 the o2's went leaner not richer.What am I doing wrong?Should I go back to only adding 13% more fuel since I had no knock or stay at 18% more fuel to keep my o2's in the 780's or should I add more fuel to try to get the o2's in the 790's.My readings at idle are:

AF 4
L8 31
bat 14.1
Int 128
BL 127
Clt 165
Ats 46
r 800
Tps .44
Iac 23
cc does not change much,TT chip uses an open loop idle,at cruise the cc goes up by 10-20 counts
Any help would be greatly appreciated.Thanks,ikle.:confused:
Generally speaking, you want to tune for as lean as possible with no knock. Some cars will have lower mv# than others. You also need to take note of the mph when the number was recorded. That needs to be factored in. The recorded # may be early on and is not indicating the top of the run. The mph is important. Holding both buttons on the sm together, it will show the mph it happened at.

To really know whats going on you need a powerlogger and a wideband. More data the better.
YOu shouldn;t really tune based on o2s they are not accurate at all. Spend the $200 and get a wideband.