DIY: Replace Fuel Tank Breather Valve (Fix for bouncing idle at fuel station)

[BOOF-M3]

Originally Posted by DToxic

This is very useful! but the pictures aren't loading for me...do you have this writeup in a pdf format you could e-mail?

Op posted in Sept about the picture issues and it looks like he hasn't posted in a few weeks. What photos are you looking for? I'm pretty certain I took some when I did mine.

Edit: my apologies, you were asking him to email them directly to you. I'm sure he will when he sees this.

[Fr0gman]

hope so! this would be a very useful DIY since my car has the issue intermittently.

[BOOF-M3]

This won't help much but once you take the plenum off it's in the top right drivers corner. It's really an easy swap, about an hour DIY at most if you have ever had the plenum off before, if not then maybe 1.5 hours.

[msan]

I don't know how you guys are pulling off the connector, I had a bad time trying to get the connection off the valve. What are your secrets?

[BOOF-M3]

Originally Posted by msan

I don't know how you guys are pulling off the connector, I had a bad time trying to get the connection off the valve. What are your secrets?

Mine came right off.

[EJT86]

Originally Posted by msan

I don't know how you guys are pulling off the connector, I had a bad time trying to get the connection off the valve. What are your secrets?

If you unplug it from the other end you can take the valve and back hose out completely and it’ll be a little easier. It’s a coller connection and it’s along the drivers side where the wheel well indent is. I saw a video that said to use a pick set but I resorted to fighting with it until it broke so either way works

[EJT86]

Originally Posted by DToxic

hope so! this would be a very useful DIY since my car has the issue intermittently.

Honestly it’s really self explanatory take the plenum off unplug and disconnect old one reconnect and plug new one

[msan]

Originally Posted by EJT86

If you unplug it from the other end you can take the valve and back hose out completely and it’ll be a little easier. It’s a coller connection and it’s along the drivers side where the wheel well indent is. I saw a video that said to use a pick set but I resorted to fighting with it until it broke so either way works

Yeah mine ended up mangled .

[drrust]

Originally Posted by msan

I don't know how you guys are pulling off the connector, I had a bad time trying to get the connection off the valve. What are your secrets?

Yes that back connector is difficult. As recommended before follow the hose along the firewall. There is a twist connection there. That way you can work with the piece without leaning over the engine. It seems you have to push the fitting towards the valve before pressing the tabs.

Swear at it a lot too!

[GORDON.M3]

That rear clip is such a PITA to remove...

[roastbeef]

i just tackled this job this weekend with the help of this DIY and it was great. thanks for the detailed contribution.

that rear clip that everyone is talking about sucks. i took the front tube off, then i removed the actual valve from it's mount, and i was able to rotate it to get a better grip of the clip. i actually used some pliers to pinch the collar instead of the lower part of the clip and it came off pretty easy. when i reinstalled the clip- i saw how it confuses everyone. the stippled part of the clip slides rearward, rather than pinches together. its an odd clip.

[spazzyfry123]

THANK YOU OP!

Originally Posted by elm3

I would like to say thank you for the write up. This actually fixed my problem. I actually had two problems. One was the ICV, which I had a code for it. and the other one was the idle fluctuation and stalling, which I thought it was due to the damaged ICV, but it wasn't. It ended up being the fuel tank breather valve. Once I changed this, it worked and the engine idle as smooth as when new. So if you have this problem with no code, please go ahead can change the fuel tank breather valve.

I occasionally get the intermittent idle and have stalled a coupe times. CEL came on right before the idle issue. I've done a smoke test and determined it is the fuel tank breather. Thinking I'll go ahead and change out the ICV while I'm in there. Thinking of tackling it this weekend.

[BOOF-M3]

Originally Posted by spazzyfry123

THANK YOU OP!

I occasionally get the intermittent idle and have stalled a coupe times. CEL came on right before the idle issue. I've done a smoke test and determined it is the fuel tank breather. Thinking I'll go ahead and change out the ICV while I'm in there. Thinking of tackling it this weekend.

So "this" weekend has passed. Did you end up tackling it or were you too busy helping other members with their beautification mods?

[spazzyfry123]

Originally Posted by BOOF-M3

So "this" weekend has passed. Did you end up tackling it or were you too busy helping other members with their beautification mods?

Let's see... two weekends have passed and I've done NOTHING.

Something something can I not be an adult anymore something something

[SoCalRPM]

Thanks, OP. Needed this. Sounds like something that'll be worth doing when replacing spark plugs

[donlee1085]

Awesome right up, I will be ordering the part this week. For almost a year I've been experiencing bouncy idling and stalls every once awhile (while at a complete stop). Also, smell of fuel inside the cabin.
As of the past month, been dealing with starting issues after fueling up.

Ran codes recently, ended up changing the DTML valve and the gas cap cover. Even with the two parts swapped I still get the gas cap light and p0442 code. I'm hoping this replacement will solve my issues.

[BOOF-M3]

Originally Posted by donlee1085

Awesome right up, I will be ordering the part this week. For almost a year I've been experiencing bouncy idling and stalls every once awhile (while at a complete stop). Also, smell of fuel inside the cabin.
As of the past month, been dealing with starting issues after fueling up.

Ran codes recently, ended up changing the DTML valve and the gas cap cover. Even with the two parts swapped I still get the gas cap light and p0442 code. I'm hoping this replacement will solve my issues.

It is definitely worth doing. The only issue is disconnecting the valve from both clips as others have mentioned. But you will be fine.

[donlee1085]

My replacement part came in this past Friday and swapped it out later the night. Job took me a little over 3 hours, given it was my first time taking off the air intake plenum and I was taking my time. The only part that took some time was taking the tubes off, other than that it was straight forward.

Thank you OP and others for the useful information, it made this job a lot easier than expected. So I would like to contribute to this thread as I’ve been experiencing symptoms for over a year prior to getting this part replaced.

Signs I experienced at the beginning:
-Bouncy idling, engine sometimes stalls/turns off.
-Gas cap light came on the dashboard, came on one morning then went away.
-SES light came on for increased emissions, which also would intermittently turn on and off over time.
-Smell of fuel inside the cabin.

My mechanic wasn’t able to figure the cause of the problems at first. He thought it could’ve been something with the ICV or A/C compressor, but no codes were popping up. At this time, he replaced both throttle actuators and all spark plugs. I was getting a TA code for bank 1, decided to get both of them done. There was a code was coming up for a coil, attempted to swap them out but then threw another code for a different cylinder. So with both TAs replaced, decided to keep an eye on it.

Months passed then these signs/symptoms were predominantly present:
-SES light STAYED on for increased emissions
-Smell of fuel inside the cabin was occurring more frequently
-At times, a notable noise could be heard during start-up, a vague *burnt* smell would be present for a few seconds inside the cabin.

Soon after a couple months later, it was THESE additional symptoms (to include the ones above) that I decided to start taking a look into:
-Engine runs rough during cold start up. I would need to give it a bit of gas in the beginning during the cold start. If not car will either stall or go into limp mode.
-Hesitation during acceleration, especially at WOT under 3-3.5K RPMs. Continuing to go WOT under 3.5K RPM will throw the car into limp mode.
-Decelerating while down shifting will cause the car go into limp mode.
-Cruising at a low speed (15-25mph in 2nd gear in a neighborhood, school zone, etc) would go to limp mode.
-Car SHUTS OFF completely when car is in neutral and getting out of gear, RPM drops straight to zero.
-Car stalls after fuel up. Would need to be on the gas, eventually the car will run on its own.

The issues were giving me a headache, had a diagnostic done when it was serviced for an oil change, 2 pages worth of codes were given to me by my mechanic, to include misfires on all 8 cylinders. He insisted on changing all my spark plugs and possibly my coils as well. ///M for money he noted lol.

So after a reset, gas cap light came back on followed by spontaneous engine stalls leading to limp mode. Restarted the car and SES light on the dash with less misfiring. Decided to drive it easy until I got these issue resolved.

One of the codes appeared was the DMTL pump. Did some research and decided to order the pump along an ODB2 scanner. Swapped out the part and cleared the codes. Ran fine for a day or two but then the gas cap light warning came followed by the other issues.

Decided to swap the gas cap. Ran codes prior to reset. What was 20+ codes narrowed down to 9.
-P0301-P0308, P0300 (misfiring in all cylinders)
-P0442 (small detection leak)

Did some investigation of the P0442 and lead me straight to this DIY. Very happy I was able to pin point the cause of my issues. Since I’ve replaced the part, noticeably difference between night and day. Thank everybody again for the useful information.

[e92m3sf]

Does anyone know if there are any negative side effects to the car if you have this problem and don't replace the valve? As far as I know, it's only the bouncing RPMs for a minute or so after you fill up gas. Can it do some potential damage?

[EJT86]

Originally Posted by derekc5475

Does anyone know if there are any negative side effects to the car if you have this problem and don't replace the valve? As far as I know, it's only the bouncing RPMs for a minute or so after you fill up gas. Can it do some potential damage?

I’d imagine if your valve isn’t purging fuel vapor, your vapor canister will flood and need to be replaced as well making an $80 repair into a $400 repair

[drrust]

Originally Posted by derekc5475

Does anyone know if there are any negative side effects to the car if you have this problem and don't replace the valve? As far as I know, it's only the bouncing RPMs for a minute or so after you fill up gas. Can it do some potential damage?

One will get an occasional stall too. May only be an inconvenience, but could be an issue in some situations.

[RC Post]

I've been having this bouncing idle and stalls out only on morning cold starts and no other time thru out the day.. No codes.

Should I give this a go?