This is a track only car, not registered for the street, so the legality of not having the emissions system intact is not my concern.

I removed almost all of the Evap Purge system. The charcoal canister is gone, all the vent lines, and the 2-way valve back at the tank have been removed. The purge soleniod is still mounted on the intake manifold and hooked up to the ECU, but I put a vacuum cap on the valve control port (the one that runs to the top of the charcoal canister and actuates the diaphram valve), so I'm expecting the solenoid to still actuate and the the ecu shouldn't throw a code for that.

My actual question/concern revolves around the 2-way valve back at the tank that is inline between the charcoal canister and the gas tank. In it's place, I installed a small inline fuel filter, and some tubing running up the fill pipe, so it can vent to atmosphere, but not get any dirt or water into the tank. The manual says the 2-way valve opens to allow fumes to travel to the canister, and I know that if you leave the gas cap off, sometimes you'll get a Check Engine light for this, so I'm wondering, now with the setup I have, am I going to get any cel codes for the tank being able to freely breathe, or should I put the valve back in, but still run the vent line to open air?

I rely on my check engine light while racing to know if there's a serious problem, and I don't want to throw a race by having to come into the pits just because the ECU didn't feel there was enough vacuum/pressure in the tank.