Noob question on lean cruise

[davepl]

As I work my way through the tuning FAQs, I'm hoping someone can gently answer a basic question for me.

On the LS7 where should I be looking to adjust the AFR for steady state, light-throttle cruise? From the dyno WOT is all perfect now but cruise is still lean.

I know that open loop will take over if open loop tables are richer than PE tables, but really I don't know where to focus.

Thanks,
Dave

[schpenxel]

Is it in open loop or closed loop? Mods? Tune? Logs?

[davepl]

Heads and cam, closed loop. No logs handy, all I know is it's very lean on light throttle cruise.

[schpenxel]

Long tubes or factory exhaust?

Lean based on what? WB or narrowband O2 readings? Where is the WB located? Are there any exhaust leaks? What does injection timing look like? Stock?

There are too many variables to think about, that's why a tune/log are extremely helpful.

The bottom line is the ECM uses the factory narrowband O2 senors to drive fueling towards lambda = 1 ANYTIME you're in closed loop. If fuel trims aren't maxed out then the computer thinks you're +/- 14.7:1 while cruising. A log would confirm this. Now.. it could be totally wrong due to a number of things, but no matter what you change the MAF or VE tables to, fuel trims will add/subtract fuel to get back to the same place it's at now. You need to figure out what is wrong.. either injection timing, exhaust leak, WB O2 calibration.. fuel trims maxed out.. SOMETHING else is going on.

That's why I wanted to see a log and tune. Either your WB is wrong or something else is going on. There is no simple way to make closed loop fueling richer.