My timing advance seems to be cycling up and down for some reason without there being any spark knock or retard...



Any suggestions?

I attached the log and tune.

Also, why does the actual AFR never quite eqaul the commanded? Is the wideband just not accurate enough or is there something else at play?

 

I'm not to quite sure if this correlates with your initial question, but I see another problem. Take a look at your primary O2 sensor bank 2 readings. They are extremely low, 43 as opposed to ~438 on bank 1. That could be causing some confusion to the computer thinking that bank 2 is extremely lean, thus trying to add fuel, or possibly retard timing when it sees a decrease in manifold vacuum as a means to protect the engine from detonation. Bad O2 sensor or wiring?

 

I am using the wideband on bank 2 to simulate the narrowband. So the sensor in bank 2 is actually my wideband. In any event, the switch points are at 450, so because its below that its still reading lean and therefor not switching.

This was done in open loop.

Found out the cycling was the A/C kicking in.

 

Good deal, that makes sense now. I was unable to open your tune or log as I run EFI live and not HPT. Glad you figured it out.