P0455 Large evap leak on my G35

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So i've been battling this evap leak for the last 2 years or more. Yes, i know i'm throwing parts at it. CEL comes and goes. Sometimes i clear the fault and after a drive cycle it comes back and sometimes it doesn't come back for 3 months and it passes readiness monitors. This leads me to believe its like a part that not fully sealing when it should be. Goings on the forums a large leak means its likely the vent valve that is on the canister. Most people report that to be the fix. 1. I buy new OEM gas cap, cheap $20 item. 2. I grab a used whole canister assembly. Came with vent valve as well. 3. Bought a Autozone purge valve, that sits near the engine bay. I did all of these and spaced them out and i still have this fault. This somewhat leads me to believe it could be a broken vac line or something harder for me to find. I have a state emission, its only OBD2 check coming up next month and go figure car wants to constantly fail. Looking for a few more hail marys before i take it to the shop.
 
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Since you live in a metro area where I'm sure lots of salt is used in the winter, what about rust around the filler neck where you put gas in? Also, what mehullica said.
 
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Have you checked the fuel tank pressure sensor? It's part of the evap system and reads pressure in the fuel system to detect evaporative leaks. When the sensor detects a leak, or if the sensor itself fails, you'll get a CEL.
 
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Right, I start with the gas cap too and then follow the filler tube to the tank & surrounding tubes on the fill tube. You may have some rotted tubing going to the top of the gas tank where you can't see them.
 
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Bah..if u have a good indy Id bring her in for diagnosis at the minimum. I had similar issue and it ended up being a sensor that sends unburnt fuel back to the charcoal canister...cheap fix that I would not have been able to figure out myself...i did replace my gas cap 1st but stopped short of canister swap..$$. It was on a different car though, but just sayin.
 
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On my two of my Infinitis of that generation, I had to replace the valve at the canister to fix that same DTC. That being said, it never hurts to confirm your specific case with the smoker.
 
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bowlofturtle

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Originally Posted by chemman
Since you live in a metro area where I'm sure lots of salt is used in the winter, what about rust around the filler neck where you put gas in? Also, what mehullica said.
After all my parts throwing at it, this was what I suspected. Finally caved in and took it to a shop to smoke it, turns out there was a rust hole at the filler neck. $250 dealer only part and 3 hours to R/R. A little out of my capabilities at home to drop the tank a little to get to the area. I would get a smoke machine but i also need to invest in a scantool with di-directional controls to turn on/off the purge valve as well. I realized this as i was about to order up the smoke machine linked on amazon.
 
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