EVAP Headaches!
Thread Starter
Super Member
Joined: Aug 2018
Posts: 697
Likes: 172
From: Seattle, WA
2019 M5 Comp, 2005 Ariel Atom 2
EVAP Headaches!
Before: occasional CEL P0455, car also would not fill to full when fueling.
Replaced: Evap solenoid under the hood, genuine Metc fuel cap, and I tossed a (supposedly) good, used low mileage charcoal canister.
Now: Sets CEL aftet 1 drive cycle, so problem is worse than before. I've vacuum tested the line from the solenoid to the canister and it holds, same with the line from solenoid to intake manifold. Solenoid is closed when off, and vent valve on canister is open.
This problem is driving me crazy!
Question: Should I be able to pull and hold a vacuum on the line from the canister to the fuel tank? It does not hold, so I'm thinking that's the problem if it's supposed to be closed. I even took the cap off and sealed the filler neck with a rubber glove and rubber band, I can see it suck in slightly when I first apply vacuum but it falls right back down again... Any insight appreciated!
Replaced: Evap solenoid under the hood, genuine Metc fuel cap, and I tossed a (supposedly) good, used low mileage charcoal canister.
Now: Sets CEL aftet 1 drive cycle, so problem is worse than before. I've vacuum tested the line from the solenoid to the canister and it holds, same with the line from solenoid to intake manifold. Solenoid is closed when off, and vent valve on canister is open.
This problem is driving me crazy!
Question: Should I be able to pull and hold a vacuum on the line from the canister to the fuel tank? It does not hold, so I'm thinking that's the problem if it's supposed to be closed. I even took the cap off and sealed the filler neck with a rubber glove and rubber band, I can see it suck in slightly when I first apply vacuum but it falls right back down again... Any insight appreciated!
Thread Starter
Super Member
Joined: Aug 2018
Posts: 697
Likes: 172
From: Seattle, WA
2019 M5 Comp, 2005 Ariel Atom 2
I thought so, but is it not supposed to be open when not powered? I provided 12v and it clicked, with it off (unplugged) I can blow into it and it's venting. The filter inside of it looks brand new too.. or is there another valve inside the canister I don't know about?
Super Member
Joined: Jul 2019
Posts: 733
Likes: 298
From: New Orleans
2014 GL450, 1992 W140 300SD, 1993 W140 300SE, 1987 E30 Convertible
The filter inside always look new. It is not a filter, but a evaporation absorber.
There is a post in 164 section how to check things around. Clicking valves mean nothing it the rubber seal can't hold vacuum.
There is a post in 164 section how to check things around. Clicking valves mean nothing it the rubber seal can't hold vacuum.
Thread Starter
Super Member
Joined: Aug 2018
Posts: 697
Likes: 172
From: Seattle, WA
2019 M5 Comp, 2005 Ariel Atom 2
I fixed this, finally, issue was the seal between the vent valve and canister. Since you can't buy it separately I ordered another charcoal canister on Ebay just to get the seal, turns out they sent a brand new one for a whopping $75. Light has been off for a week now with lots of miles put on it and it would come on in two drive cycles before after resetting. Hooray!
