[ICARUS54]

I have an n54 with a lean condition (long term fuel trims +10~ idle, +25~ nonboosted acceleration, levels out under boost) I tried smoke testing my car and found a small leak from one of my BOVs when testing from the charge pipe, however when testing from the oil cap a ton of smoke starts exiting from the rear turbo area. I also found that there's a lot of smoke in the rear inlet but hardly any in the front inlet. red herring, pcv diaphram leakage, any ideas?

[ICARUS54]

I did only now remember that the PCV outlet is into the rear inlet, which explains a lot of that.

[TunafishE93]

Sounds like the "check valve, charge air suction line" which is described in number 14 BUT i am pretty sure the diagram is a typo. Number 14 description should go to number 12 in the picture and vise versa.
So the picture shows what should be happening with vacuum in the manifold: idle, light acceleration, cruising. Number 12 in the picture should be closed, i believe yours is open, this is letting unmetered air into the vacuum side of the intake manifold thru valve 14 which should be open causing a lean condition.

Saying this, i dont think the check valve on the charge air suction side is replaceable, I THINK its built in. The "check valve, manifold" is replaceable and is also called the pvc valve.

The second picture i wrote some numbers for the two different valves, the number 1 is the valve that i think is bad, number 2 is the PVC valve. One way to test, if you can get to it, is disconnect the hose from number 1 and cap it off (valve cover side, not hose side). This should be closed at idle, see if your trims improve or if you have nothing to cap it, put your hand over it and see if you have vacuum (which you shouldn't at idle). If so you know that is the problem.