Well, the thing that gets me is the tune hasn't changed, then it started oscillating. Before that the power delivery was very nice. That's what leads me to think it's o2 feedback related or maybe a boost leak.

On another note, why don't you want o2 feedback on at WOT? It would seem to me that you would want it most at that point. Right now as the car sits it cruises at 14.7, nice and steady.

 

The reason you don't want O2 feedback at WOT is because you don't want your engine to rely on an O2 sensor under that kind of stress. The other reason is that you simply don't need it to have a nice flat a/f ratio. As you are seeing right now your O2 has failed you. It's no big deal at part throttle but going WOT could really hurt something.

As long as your base fuel map and temperature correction tables are dialed in, you shouldn't need closed loop at WOT. Just something to note is that stock ecu uses open loop at WOT, seeing that they only have a narrow band O2 sensor and can only read values right around 14.7:1.

Another reason your boost might be oscillating is because your error feedback values are too high, meaning your base values are so far off target, that your error table is having to compensate too much. It looks like you are overshooting badly with that spike and then the feedback is bringing it back down. You might consider lowering your base values a little bit more.

 

I totally understand what you are saying and that makes sense to me. One other question, if O2 feedback is enabled, how do I tell WHEN it is enabled, WOT or not??

 

Just look under fuel->o2 sensor feedback and then click the top menu item and you look at your options. There is a max rpm and max load. Another important value is min coolant temp as that ensures the sensor is warmed up before using it.

 

OK, so the max rpm is 5500 with a max load of 8 psi, min rpm is 1000. So apparently it's not in closed loop mode when WOT. Thanks for helping me figure this out. The oscillation must be related to the boost control.

Min coolant temp is 90°F. Again, I really appreciate the help you guys have given me. I've learned a lot in the last week!

 

I'm with FRE: you might need to pull your base values down across the board.

Optionally, your boost/target table may be hosed. It is set to reference the boost target speed table for the amount of desired boost, it then looks at your Boost WG base duty map and pulls down the duty cycle accordingly to reach the desired boost.

That is IF you set it up right for every point on the target comp table.