[Alpine TSi]

Ok, so if you were to have a boost leak, since your MAS is before your turbo and IC, you would be losing metered air. Therefore the ECU will add more fuel than is actually needed, which would create problems while under boost, bucking, backfiring, etc... I had a similar problem when my ECU was acting up last summer and I would go under 10:1 with any amount of boost than the car would hate me and buck real hard for a moment until all the unburnt gas got out of the cylinders. Now when you add fuel by richening the sliders on DSMLink, yes you would be adding even more fuel and not helping anything at all, and causing the symptoms you list. So yes, your thinking is correct in your situation. For those of us that have MAF-T's in blow through it doesn't matter because the air doesn't get metered until it going into the TB, so there would have to be a pretty big leak there to cause anything. Not that buying a GM MAS setup is the fix, as it only hides a problem, but just the other scenario, which obviously doesn't apply to you.

Get those leaks taken care of and go from there. Also, are you using a wideband O2? Or are you just going off of the claculation that DSMLink makes for you? If using DSMLink, do you have its individual settings set right? Then also you have to realize it is going off of data that also involves your MAS, which isn't telling the ECU the right info with all those boost leaks. Plus in the end the AF ratio function built into DSMLink is just an estimation, not something I would completely rely on. IE to get the backfiring and such you are now, you are probably going a lot lower than 11:1 like it said.

Hope this helps.