Carbon canister filling with fuel - Bimmerfest - BMW Forums



Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E90/E91/E92/E93 (2006 - 2013)

E90/E91/E92/E93 (2006 - 2013)
The E9X is the 4th evolution of the BMW 3 series including a highly tuned twin turbo 335i variant pushing out 300hp and 300 ft. lbs. of torque. BMW continues to show that it sets the bar for true driving performance! -- View the E9X Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 05-14-2019, 05:04 PM
cbertrand cbertrand is offline
Registered User
 
Join Date: May 2018
Posts: 5
Mein Auto:
Carbon canister filling with fuel

My carbon canister is filling with fuel. Any ideas how this could happen?

It seems like it happens when the tank is over about 3/4 full. I was thinking it may be a problem with the vent connection inside the tank that goes to the fuel pump top hat on the passenger side.

I recently installed a Precision Raceworks Stage 2+ LPFP.
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 05-14-2019, 07:43 PM
gbalthrop gbalthrop is offline
Officially Welcomed to the 'Fest
Location: Fairfax County, Virginia
 
Join Date: Mar 2017
Posts: 2,234
Mein Auto: 2007 328xi E91
Quote:
Originally Posted by cbertrand View Post
My carbon canister is filling with fuel. Any ideas how this could happen? It seems like it happens when the tank is over about 3/4 full. I was thinking it may be a problem with the vent connection inside the tank that goes to the fuel pump top hat on the passenger side.
Presuming you have an N54, here is a link to a similar forum thread on the topic, and I attach a diagram from Bentley that shows the plumbing for the tank filler vent, vapor tube to the DMTL Pump & Charcoal Canister, and purge line from the Canister to the Fuel Tank Vent/Purge Valve and Intake.
https://www.e90post.com/forums/showthread.php?t=1613441

Apparently "topping off" or squeezing the Gas Pump Nozzle handle several times after the initial shutoff causes "overfilled" liquid fuel to be forced into what is supposed to only be VAPOR tubes and into the DMTL & Canister.

Do you have the practice of squeezing the pump handle several times after initial nozzle shutoff? Have you had SES light immediately AFTER filling at the pump? Have you had a "TOO RICH" Fault Code: P0175, P2190, or 29E1? If so, consider quitting pump fill prior to nozzle shut-off & at least do NOT "top-off."

Please let us know your thoughts & experience,
George
Attached Thumbnails
Click image for larger version

Name:	Fuel System, N54.jpg
Views:	32
Size:	70.4 KB
ID:	851835  
Reply With Quote
  #3  
Old 05-14-2019, 09:33 PM
08 335Ci 08 335Ci is offline
Officially Welcomed to the 'Fest
Location: Pocono Mts. Pa USA
 
Join Date: Nov 2011
Posts: 799
Mein Auto: 2010 335 M sport
Quote:
Originally Posted by cbertrand View Post
My carbon canister is filling with fuel. Any ideas how this could happen?

It seems like it happens when the tank is over about 3/4 full. I was thinking it may be a problem with the vent connection inside the tank that goes to the fuel pump top hat on the passenger side.

I recently installed a Precision Raceworks Stage 2+ LPFP.
That's a good place to start looking. At least that's where I'd start.

It's possible the tank is building excessive pressure due to the increased fuel flow recirculating back into the tank from the pressure regulator. Normal driving could have the fuel sloshing into the vent tube then being forced into the carbon can. If you leave the fuel cap slightly loose does it still do it?

Either way you're going to need a new carbon can. Once you get liquid fuel into them, they're shot and will never work properly again.

I see you've posted this to N54Tech.com, so I assume you have a JB4 installed. Have you run a log checking your LPFP pressure?
__________________
No matter how fast I go, there's always someone slower in front of me.

2010 E92 335 M Sport, Titan Silver Metallic, Steptronic, JB-4 G5 ISO, WMI, 3.5 Tmap (22 psi boost), BEF, Front Strut Brace, SS brake lines, Drilled and Slotted Rotors, Anti-lag, OCC, Pedal tuner, Escort Max 360

Gone, but not forgotten ( totaled)
'08 335 E92, M-Sport suspension, 6 sp auto, w/paddle shift

CCA Member 109065 since 1993

CQ ... CQ...Kilo Charlie 3 Bravo Whiskey Zulu calling CQ


Last edited by 08 335Ci; 05-14-2019 at 09:53 PM.
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old 05-14-2019, 09:56 PM
cbertrand cbertrand is offline
Registered User
 
Join Date: May 2018
Posts: 5
Mein Auto:
Unfortunately I donít think thatís the problem. Car has thrown a DMTL code only and I replaced the DMTL pump last weekend. Before I replaced the DMTL pump, I ran all the gas out of the tank and blew out every line from the canister to the fuel filler neck, tank, and purge valve in the engine bay - everything was dry and clear, including the carbon canister. I also removed the LPFP top hat and inspected it and the vent line connection in the tank, which looked ok. I then put about 15 gallons in the tank (it has a 16 gallon capacity) and everything was fine until today, when it was down to about 3/4 of a tank.

I first realized there was a problem a few weeks ago when I would get intermittent rough idle or hesitation while driving at a constant speed, and fuel leaking/smell from the rear passenger tire area. After some data logging (low STFT and low AFR) and reviewing the diagram you referred to, along with some other EVAP system diagrams and functional descriptions I found on this forum and others, I concluded that the carbon canister is filling with fuel somehow and the liquid fuel is being dumped into the engine when the purge valve opens.

I plan to run my current tank of gas out and make sure the system is dry again, then fill up and immediately check the carbon canister for fuel.

I canít figure out how gas is getting into the canister. Iím thinking there is a problem with the vent line inside the tank and I canít inspect the inside of the tank to make sure..

Do you have a drawing of the lines inside the tank? Would I be able to find a drawing like that on the TIS website?
Reply With Quote
  #5  
Old 05-14-2019, 10:04 PM
cbertrand cbertrand is offline
Registered User
 
Join Date: May 2018
Posts: 5
Mein Auto:
Quote:
Originally Posted by 08 335Ci View Post
That's a good place to start looking. At least that's where I'd start.

It's possible the tank is building excessive pressure due to the increased fuel flow recirculating back into the tank from the pressure regulator. Normal driving could have the fuel sloshing into the vent tube then being forced into the carbon can. If you leave the fuel cap slightly loose does it still do it?

Either way you're going to need a new carbon can. Once you get liquid fuel into them, they're shot and will never work properly again.

I see you've posted this to N54Tech.com, so I assume you have a JB4 installed. Have you run a log checking your LPFP pressure?
Didnít see this response till after I posted my previous reply....

I will try loosening the cap and see what happens. I have a stock fuel pump on the way to try as well. I do have a new canister, but wanted to make sure the problem was solved before I replaced it.

I have MHD stage 2+ and I have been logging every time I drive it for the last two weeks. LPFP pressure is typically in the 72-75 psi range.
Reply With Quote
  #6  
Old 05-15-2019, 11:46 AM
gbalthrop gbalthrop is offline
Officially Welcomed to the 'Fest
Location: Fairfax County, Virginia
 
Join Date: Mar 2017
Posts: 2,234
Mein Auto: 2007 328xi E91
Quote:
Originally Posted by cbertrand View Post
Unfortunately I donít think thatís the problem. Car has thrown a DMTL code only and I replaced the DMTL pump last weekend.
What Fault Code & Definition did you see as "a DMTL code"? Any chance it was Purge Valve or Tank Vent Valve code? Perhaps 2A1A, P0440, P0441, or P0443? As I understand the system, the DMTL Pump ONLY runs after the engine is OFF, and the Tank Vent Valve or Purge Valve has CLOSED.

Those codes ALL relate to an issue with the Purge Valve or Vent Valve at the intake which is supposed to open when engine is running & warm (as controlled by DME). Obviously, if that valve does NOT OPEN during engine operation, to purge fuel vapor from the canister, the charcoal in the canister will get saturated with fuel vapor and you will get fuel odor around the right rear wheel. I presume there is ALSO something equivalent to a "2PSIG" valve (pressure/vacuum release valve -- two-way) on the "Fresh Air Vent Line" that is shown as item #21 on the Bentley diagram I attached to prior post, and if that valve is NOT closing when engine is OFF, then fuel vapor escapes to the atmosphere (in RR wheel area).

I've never disassembled, inspected or dissected the Evaporative Emissions system on mine, so this is ALL theoretical to me, but I wonder HOW you have determined that your canister is "filling with fuel"? That implies that fuel in "liquid state" is somehow getting into the canister. It is also theoretically possible that the charcoal in the canister is absorbing fuel from vapor over the liquid in the tank (as it is supposed to do), but that vapor is NOT being purged due to improper vent/purge line/valve operation, and under certain pressure/ temperature conditions the fuel vapor is condensing into liquid form in the canister.

George
Reply With Quote
  #7  
Old 05-15-2019, 12:20 PM
cbertrand cbertrand is offline
Registered User
 
Join Date: May 2018
Posts: 5
Mein Auto:
I got 2B3A and 2B3D, which I think are both related to current draw from the DMTL pump. If that is true, it makes sense that if the pump was full of fuel, it would affect the current draw.

Last night I disconnected the hose that runs from the carbon canister to the fuel filler vent and about 8 ounces of liquid fuel poured out of the carbon canister. I had taken everything apart last Saturday and the carbon canister and all lines were dry, so I think the fuel is coming from the tank vent.
Reply With Quote
Reply

See More Related BMW Stories


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E90/E91/E92/E93 (2006 - 2013)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
the VERY best of E39 Links chivas E39 (1997 - 2003) 104 12-20-2018 03:06 PM
How much fuel does it take to 'cover' (i.e., cool) the BMW E39 electric fuel pump? bluebee E39 (1997 - 2003) 90 04-30-2015 10:01 PM
What are you paying for Diesel? Flyingman BMW Diesel Owners & Enthusiasts 175 02-23-2012 06:11 AM


All times are GMT -7. The time now is 09:21 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
© 2001- VerticalScope Inc. All rights reserved.