wideband?

[banyasracing]

i had my 06 cobalt ss/sc on the dyno and w/ the wideband for the dyno im getting 11.6 steady, but w/ my aem eugo wideband readings im getting 10.8 in 2nd gear and 3rd gear drops to 10.0(on the street) my aem is brand new and the dyno wideband was calibrated before we started. do i need to calibrate the aem or could it be a different problem?

[Julex]

Well a Dyno Wideband sniffer will always be off from a wideband that is before the catalytic converter, as for the wideband drop in afr, does your commanded change? do you compare the AFR to each gear say 2nd at 4k and 3rd at 4k and 4th at 4k.

Also a log file will help people know what you mean, basically need to look for if COT enabled or Piston protection enabled, both of those could be a culprit.

[zzzybil]

i understood the aem and sniffer are taking values from different locations . ............pre and post cat etc

but you lost me
on the 2nd , 3rd and 4th gear @ 4k afr comparing
commanded changing ?
COT and piston protection - enabled being the culprit

i know theres a pearl or 2 in there !!!
........ could you expand on that justa lil bit
thanks

[redhotjamedjimi]

things that change commanded afr. Cat Over Temp adds to the PE. Ex. (cot max).16 + (pe)1.3= 1.46 commanded. 14.6/1.46. 10.06 Afr. thats what precat should read at high loads ie. 2-3-4th gear. 1st gear may not have enough load for COT to come into play.

gm also raises the COT temperature thresholds, everyone should do about the same. And Piston protection can be eliminated with rich enough PE's and tuned MAF and VE.