427 LQ9 giving lean bank 1 & 2 error inregulary after WOT

[autofil]

Hi!

Please bear with me...

I have a custom built & pre-tuned, stroked LQ9 427 with new VCM, all from Turn Key Engine Supply in CA. Great response, but quite high knock rate from 4000 RPM and up at WOT, particulary after the local high octan is no longer available in my area. I can feel the retard of the spark advance and the loss of high end Power. The VCM throws in error codes for lean bank 1 & 2 after WOT runs, not always, but sometimes. This may indicate a too lean AFR. I do not want to retard the spark advance to get rid of the knock, rather increase the PE to reduce the AFR in the high RPM / WOT range, and prevent the knock effect with more fuel.... I have a WB to log any changes.

Any suggestions for the way forward...? Please Reference the Attached tune and log run.

PS! I could use octan boosters, but this is not to effective, nor not to sound for a daily driver

Thanks!Ny orginal tune 13.11.2013 med ny motor, rev 15.hptlogg 20.04.2014.hpl

[jimmyblue]

Lean error needs your LTFTs to be driven all the way to +25%.
That should take a long time to creep that far, and not happen
during WOT because no trimming goes on.

I'd guess that you have some O2 sensor problems and a base
of false trimming that's got you close to the edge to start,
and the pinging situation is giving you a bunch of HC soot
that fouls out the sensors even worse (perhaps only until
normal running purges the goo, or perhaps not).

Before you go pushing more fuel, you want to know what's
going in. What does your wideband say, vs your commanded?
And, is there a point where they diverge abruptly, like a
fail-to-fire / misfire situation, a cylinder distribution problem
(single cylinder lean will ping when fueling is perfect) etc.?

[autofil]

Thanks jimmyblue; I will investigate a little more before changing the tune. It did Power very well prior the drop in octan Level due to discontinued high octan availability in town. I have all new O2 sensors, but still, I Guess they can foul around. I will make some more log run that are up to date. Thanks for Your input