Fuel odor after filling.

[TMR013]

Hi All!

Started noticing a strong gasoline odor in my garage, but only after I fill my tank, no odor once the gas level goes down. No noticeable leaking. Hard to pinpoint, it's only outside the car, not in the cabin, seems like it may be stronger on the drivers side, but can't be sure. Which does not make sense if it's the tank or filler neck.

I found the thread below, but was wondering if anybody else has had this issue and if you found a solution?

http://www.1addicts.com/forums/showthread.php?t=1330242

[oneBIGtoe]

Have same thing on my 2012 e88. The charcoal canister is on the list of maintenance parts at 80k. But I am not convinced this is the issue. Only happens when I fill and not overfilling.

[B777flyboy]

I have never had an issue with my 135 but any other time I've smelled gas outside of a vehicle it has always proven to be a fuel leak somewhere.

[Matticus91]

There are issues with the fuel tank vent valves on these cars, likely should be looked at by dealer.

[bbrugger]

Originally Posted by TMR013

Hi All!

Started noticing a strong gasoline odor in my garage, but only after I fill my tank, no odor once the gas level goes down. No noticeable leaking. Hard to pinpoint, it's only outside the car, not in the cabin, seems like it may be stronger on the drivers side, but can't be sure. Which does not make sense if it's the tank or filler neck.

I found the thread below, but was wondering if anybody else has had this issue and if you found a solution?

http://www.1addicts.com/forums/showthread.php?t=1330242

Not sure if you have figured this out yet, but here is what happened to me last month. I had the same symptoms with fuel smell, I first looked at the vent line from the filler neck. nothing wrong with it so I replaced the gas cap because it seemed to not seal very well. No help.

I then accidently had my car running for about 5 minutes on a pretty good incline 30 degrees or so nose up. After running for a bit I noticed a puddle of fuel under the fuel tank on the drivers side. I over estimated the ability of the sealed covers under the back seat. :-)

My fuel regulator under the rear seat on the drivers side had cracks in the top and was leaking out over the top of the fuel tank. $400.00 bucks (#FCPEuroRocks) and 45 minutes I replaced the low pressure fuel pump and fuel regulator(both under the back seat and smell is gone. That was the beginning of my ordeal, but that is a whole different and unrelated story. :-)

Hope this helps, pretty easy to check by pulling up the back seat and each cover has 4 10mm nuts the covers come right off. At least you can check that off the troubleshooting list quickly.

[oneBIGtoe]

What I don't understand about the folks mentioning to pull the rear seats. Is why doesn't it smell inside the car? Also, if its vapor leak, why doesn't it smell all the time?

[TMR013]

Originally Posted by bbrugger

Not sure if you have figured this out yet, but here is what happened to me last month. I had the same symptoms with fuel smell, I first looked at the vent line from the filler neck. nothing wrong with it so I replaced the gas cap because it seemed to not seal very well. No help.

I then accidently had my car running for about 5 minutes on a pretty good incline 30 degrees or so nose up. After running for a bit I noticed a puddle of fuel under the fuel tank on the drivers side. I over estimated the ability of the sealed covers under the back seat. :-)

My fuel regulator under the rear seat on the drivers side had cracks in the top and was leaking out over the top of the fuel tank. $400.00 bucks (#FCPEuroRocks) and 45 minutes I replaced the low pressure fuel pump and fuel regulator(both under the back seat and smell is gone. That was the beginning of my ordeal, but that is a whole different and unrelated story. :-)

Hope this helps, pretty easy to check by pulling up the back seat and each cover has 4 10mm nuts the covers come right off. At least you can check that off the troubleshooting list quickly.

Thanks for the info, wonder if you have the P/N's you replaced. I went to FCP Euro, and found the Fuel Pump Assembly Right BMW-16147163298, but what was the other component you replaced?

[bbrugger]

https://www.fcpeuro.com/products/bmw...er-16147163296

https://www.fcpeuro.com/products/bmw...mp-16147163298

[Lucky1]

Originally Posted by oneBIGtoe

Have same thing on my 2012 e88. The charcoal canister is on the list of maintenance parts at 80k. But I am not convinced this is the issue. Only happens when I fill and not overfilling.

Having the same issue. My mechanic took a look under the rear passenger side wheel weld and did a smoke test. Said there's no leaking at the front or rear of the fuel tank and he can't see anywhere where fuel vapour could be venting. Recommended replacing the charcoal canister as a test but no guarantee.

Originally Posted by bbrugger

My fuel regulator under the rear seat on the drivers side had cracks in the top and was leaking out over the top of the fuel tank. $400.00 bucks (#FCPEuroRocks) and 45 minutes I replaced the low pressure fuel pump and fuel regulator(both under the back seat and smell is gone. That was the beginning of my ordeal, but that is a whole different and unrelated story. :-)

Hope this helps, pretty easy to check by pulling up the back seat and each cover has 4 10mm nuts the covers come right off. At least you can check that off the troubleshooting list quickly.

How do you pull up the back seat? Is there no other way to investigate or rule this out? Could my mechanic have ruled this out as a problem with a smoke test?

[zx10guy]

The rear seat bench is only held in by friction. If I recall correctly when I removed mine, you just lift up from the front and it'll pull up. You might have to use some force.

[Lucky1]

So we pulled the rear seats up while I was at the mechanic and exposed both the fuel regulator (driver side rear seat?) and this underneath the passenger side rear seat which I believe is the fuel sending unit?



We are smelling fuel vapour from the passenger side and not the driver side so my mechanic is recommending replacing the gasket here first then if that does not work replacing the fuel pump/sending unit. Anyone have an opinion on this approach and whether it makes sense? I filled up an hour / 30 mile journey before getting to the shop and there was no sign of leaking fuel, just a smell of vapour.

[TMR013]

[/QUOTE]

Originally Posted by Lucky1

So we pulled the rear seats up while I was at the mechanic and exposed both the fuel regulator (driver side rear seat?) and this underneath the passenger side rear seat which I believe is the fuel sending unit?



We are smelling fuel vapour from the passenger side and not the driver side so my mechanic is recommending replacing the gasket here first then if that does not work replacing the fuel pump/sending unit. Anyone have an opinion on this approach and whether it makes sense? I filled up an hour / 30 mile journey before getting to the shop and there was no sign of leaking fuel, just a smell of vapour.



Attachment 1960371

If the pump or sender units are cracked, which I believe is the main issue. Replacing the gaskets alone will not help.

[oneBIGtoe]

Lucky, try filling up just before. The smell would disappear from mine within 20 miles or so... I will be pulling the rear seats in the spring, when car is out of storage.

[Happy Jose]

The evaporative emission system has a problem. replace the charcoal canister and the fuel filter in the gas tank.

[Lucky1]

Originally Posted by Happy Jose

The evaporative emission system has a problem. replace the charcoal canister and the fuel filter in the gas tank.

Hi, how did you come to that conclusion vs a crack in the fuel sender unit as TMR013 has suggested?

[JimVonBaden]

Originally Posted by Lucky1

Hi, how did you come to that conclusion vs a crack in the fuel sender unit as TMR013 has suggested?

Because Unhappy Jose know's all!

[oneBIGtoe]

I would not recommend just changing parts without narrowing it down a bit more, or at least ruling out some things. The only plus if you change canister, is this is a regular maintenance item... but expensive one.

[TMR013]

Originally Posted by oneBIGtoe

I would not recommend just changing parts without narrowing it down a bit more, or at least ruling out some things. The only plus if you change canister, is this is a regular maintenance item... but expensive one.

Guys I can almost guarantee it's the pump or sender unit or both. Both are just plastic so it's inevitable that they eventually fail. Plus I replaced both and that fixed the gas smell entirely. I also had my local mechanic say this is a known issue.
Kind of a pain in the ass to replace, but doable.

[Happy Jose]

Originally Posted by Lucky1

Hi, how did you come to that conclusion vs a crack in the fuel sender unit as TMR013 has suggested?

Do you know the function of the fuel sender? And why should a "crack" in it have any thing to do with a gas odor? And just how was it determined that this probably imagined crack made the sender unserviceable?

The canister is the likely problem.

[TMR013]

Originally Posted by Happy Jose

Do you know the function of the fuel sender? And why should a "crack" in it have any thing to do with a gas odor? And just how was it determined that this probably imagined crack made the sender unserviceable?

The canister is the likely problem.

The sender unit fits into the top of the fuel tank. Once placed and screwed in with the ring nut, it in essence becomes part of the fuel tank wall. a crack in that surface will allow vapor to escape the tank, ergo the fuel smell.
The sender itself, which measures fuel level, still works because the mechanism is unaffected by the crack.
Replace the canister. If it works more power to you. But think you will find you still have the smell.

[oneBIGtoe]

The challenge I have with it being anything other than canister. Is why does it not smell
inside the vehicle, and only after filling up.

This does lead me to believe its the canister.

I will still pull up rear seat and inspect the area/parts mentioned.

[Happy Jose]

Hell replace everything! Might as well while you are in there!