Gas/Exhaust smell inside cabin after doing a long, boosted pull

[phuz]

Since I've done my 2JZGTE swap earlier this year, I can't diagnose where the gas/exhaust smell is coming from. It only happens if I have a window or sunroof open and I think that is because when they are open, it creates a vacuum inside the car.

If I do a nice 2nd, 3rd, 4th or 5th gear pull, I always get a smell of gas and/or exhaust immediately afterwards for about 20 seconds. It seems that

There are no exhaust leaks.My exhaust tip out far enough so the exhaust should escape past the rear bumper.The fuel pump cover is sealed and bolted up.I relocated my valve cover breather to down behind the headlight.My blow off valve is now relocated down behind the headlight too.

I thought about hooking up my shop vac to the interior somehow and pulling vacuum on it and then using some type of smoker or fogger to see where it enters the car, but I don't really have access to one and they are quite expensive.

If I keep the windows up and sunroof closed, I don't get any exhaust smell whatsoever.Any ideas on what I am missing?

[moso]

how about the tank breather hose. it comes up the firewall near the clutch line and crosses over the firewall and goes back down by the break booster then along the frame rail terminating at the canister. there is a rubber hose just as it clears the starter. could that have failed and your getting gas fumes sucked in the cowl vent.

[phuz]

After the swap, I no longer have a breather vent up there. I have the fuel supply line and return line up there and that's it.

I even replaced that weather stripping with a thicker piece to seal against the back of the hood, so no vapors should be coming from the engine bay directly into the vents.

[Doya]

Do you have an open External Wastegate. Once I hit full boost with the windows down, the smell is so bad. Thats raw hydrocarbons, good for the lungs

Anyway, if you do, get it recirculated into your downpipe.