That's not a bad idea, too bad it's so expensive. Really the FIC should be able to do exactly that, but I just don't trust that tap configuration and results were spotty.
The Analog A IN/OUT intercept trick with the O2 works pretty well. However, it does not do a passthrough in voltage mode, so I can't just give it a .445 volt signal in boost and have it work like normal out of boost by leaving the cel values at 0 like you can with the O2 maps.
This forced me to do an offset. An offset of -.478 results in a nearly perfect "no-transition" when entering open loop. Then I pulled fuel around the transition to get just about everything at 11.5 AFR.
This took many pulls, lots of long driving logs, and lots of playing around, but the car is 100x more fun to drive now.
There are however, a few things I haven't been able to resolve. There is some lift throttle backfire still. I had quite a bit of this stock too, so it's not any worse, just something I was hoping would be tuned out with the leaner mixtures. It's because the MAF is behind the actual throttle closing, so it's not quick enough to pull fuel. I need to pull fuel when the MAF is high, but the MAP is low, but the AEM software doesn't give that option.
I actually am running with the MAF intercepted. I spent so much time getting that to work I figured I might as well have it to log, and you can actually see the MAF blip back up after lifting off the throttle.
I have a couple of theories. Either the wastegate bounces a bit allowing the turbo to spool a little and pull in more air, or the unburnt fuel is igniting in the exhaust and forcing the turbo to spool.
Here's a picture of the MAF blips after letting off the throttle.
The other issue I was hoping to be able to solve with the AEM is the initial delay spike in fuel delivery when you plant your right foot at low <2k rpms.
You can see it very clearly here.
After my foot goes to the floor, there is a long delay until the PCM starts adding fuel, resulting in a huge spike in fuel delivery. There are also a couple blips in the fuel beforehand, like the PCM is trying to add fuel, but something is holding it back.
The RPM that the spike occurs differes between runs. I've seen as low as 2400rpm and as high as 3000rpms. So I don't know how the PCM is switching over. It could be from the MAF I suppose, but that isn't exactly the same every time either, ranges between 3.5V to 3.7V.
Actually now that I think about this could be the VCTS, but the strange thing is there is no sudden spike in MAF voltage or AFR, so that leads me to believe the PCM knows to add fuel when it opens the VCTS flaps and not before. So I am not sure removing the VCTS alone would help. This might actually require a standalone.
Lastly there is also still an abrupt transition to open loop in first gear. My thoery is that the car only samples the O2 at about 2Hz, and that isn't quick enough to react to my offset O2 voltage signal and add fuel fast enough to keep the AFR low, and it goes up to the 16:1 AFR it loves so much before switching over. However thanks to my fuel pulling to a nice 11.5 AFR, it does give a serious kick in the pants when it goes to open loop.
I am tempted to try raising the offset to -.49V to see if it keeps first gear from ever going lean, but I am afraid that could cause the rest of my gears to go super rich. I guess I can give it a try.
What's there to lose at this point?