About a week ago my CEL came on so I scanned the car. The only code present was P0455-EVAP System-Large Leak Detected- MIL ON. I searched the Ross Tech Wiki to see what this code could point to:http://wiki.ross-tech.com/wiki/index.php/16839/P0455/001109
So before buying any parts I thought about what the last thing I did to the car was. I remembered I had filled the car up with gas the night before. So I cleared the code and tried opening the gas cap and putting it back on making sure to get 3 clicks in. During this time I had noticed the car had started to develop somewhat of a odd light throttle suggishness. It almost felt like the responsiveness of the pedal on light engagement was off. The code came back the next day on my way to work so I decided to dig in.
After making sure that all items like gas cap and boost tap were tight and installed correctly I started looking at vacuum lines. After going over the entire engine bay checking hoses to make sure none were cracked or loose I took to the forums to see what others had done. Sure enough I came up on a couple threads that referenced the N80 Valve or Purge Solenoid. I decided to check it out. I searched on the interwebz for what this part looked like and was able to find it here: http://jhmotorsports.com/shop/catalog/purge-valve-evap-solenoid-or-n80-valve-for-b7-a4-rs4-all-b8-s5-42l-c6-a6-s6-p-723.html
Before I ordered a new one I checked the wires to the plug and everything was in order. I took the old one off the car before I started taking pictures for a write up so there normally would be two one time use clamps on each end of this. Here is where it is located on the engine:
I removed the old N80 Valve and thought to myself how do you test this? I took the new one out of the box and started looking at it. I decided to put air pressure to it to see if it opened. This actually worked really well. The old one was easily allowing air to pass through the valve at 5psi. I took the new one and did the same exact test and the results were far different. At 5psi the valve did not allow air to pass through it at all.
Old N80 Valve: You need to test these because it showed no signs of external failure at all. The failure was 100% Internal.
Installed the new valve and 2 small hose clamps that i had in the garage and buttoned everything up:
https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/68912_10100775781644427_8588348639799277976_n.jpg?oh=f7db554900437f0dd1c6acf5e805358b&oe=54442D18&gda=1413664337_cf1371470bb2aa4a3558b9560c5161d1
I have now been driving code free for the last week and the odd hesitation in the throttle has gone away!!! ;D