Johns98Z28

That means I'm running rich at cruise right? When I goto WOT the Lterms goto 0. Would it be worth my while, performance wise, to get the Lterms back to -5 to 0? Am I loosing power with the #'s being that out of wack?

TIA,
John.

98TAauto

iTrader: (2)

how do you know your A/F is that at cruise? If your reading that on atap, its always gonna try to show a 14:1 ratio.

Johns98Z28

Hey 98TA,That's not my A/F reading, it's my Lterms readings.

98TAauto

iTrader: (2)

ohhh crapo! Sorry about that one... but you may need to lean you car out a tad. I think naywhere from -5 to -3 is best. What type of MAF are you running? If you want to lean it out a tad to get them up some you can just go to the MAF table on edit and Multiply 3000-6000, then scale up every cell after that by 1%(91%, 92%, 93%) untill you get to 100% and that should get your LTRIMS to -4 or so

some of the others in here should be able to assist you better also

98TAauto

iTrader: (2)

i'd probably lean the car out a bit. Does she smell rich at idle?

Im not sure if your losing any power. Ltrims dont really mean your are rich or lean, they just tell the PCM to dump fuel or not at WOT. Im guessing your WOT LTRIMS read 0??

how do the 02's look at WOT?

BTW, if you dont have a SLP 85 MAF or ported ends those would lean you out, but i'd either run a calibrated MAF or tune your stock ends.

My SLP unit maybe my LTRIMS go form -5 to +5, so if that holds the same on your car that alone would put yours in the -3 area. But dont quote me on it <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

But I doubt its hurting you up top... just read your 02's at WOT to get a baseline idea

Johns98Z28

Hey 98TA, thanks for the info. Would it be worth me fixing this problem? Am I loosing that much power? Or am I just running a little rich? Should I be worried about -13.8 to -14.4 LTerms @ cruise?

Thanks, John.

NOBR8KSS

iTrader: (12)

You are probably not losing much power at WOT. The PCM will not make any changes to the fuel map at WOT if you are running rich at part throttle. If lean the PCM will add fuel at WOT causing a rich condition and hence less power.
You should always tune your base A/F ratio first by measuring LTFTs and bring them as close to the negative side of 0 as possible (-3 is a good number to shoot for). A MAFT is a good temporary fix to the problem. Then adjust your WOT A/F ratio by bringing the O2s into the .890 range.
LS1 Edit or Predator tuning will reap even better gains because they can make much smaller changes than a MAFT.