Gasoline smell from left rear?

[W Cole]

After driving my car and pulling into the garage there is a strong gas smell from the left rear wheel area. This smell is completely unburnt fuel so I'm thinking its a leak involving the gas tank.

Anyone have any ideas?

[JEllis]

Pretty common in BMWs. My E36 is doing the same thing. If you overfilled... like topped up too much you might have gotten fuel into the charcoal filter. If thats the case its probably the easiest fix but also the most expensive.

Otherwise it might be a seal problem on the tank itself, you can look under the rear seats and see if there is wetness around the fuel pump/transmitter gaskets.

Beyond that it could be a break down on the pump/transmitter itself but its unlikely in an 09.

Other more tricky stuff to find is a leak in a line itself which will take some detective work.

[apecush]

Left rear houses a whole bunch of emissions equipment including the charcoal canister. Sadly, I know this because I was rear-ended and there was about $1k of damage to emissions equipment in that area. You could have a split charcoal canister or a damaged hose - I'd recommend taking the car in for a check up.

[W Cole]

Thanks guys. I'll pull the seats and take a look, although I dont smell anything inside the car.

Whats the best way to check out the charcoal cannister? Through the wheel well?

[Malek@MRF]

Check to see that you aren't leaking at the injectors or the fuel line.

[W Cole]

Originally Posted by Malek@MRF

Check to see that you aren't leaking at the injectors or the fuel line.

Thanks for the reply Malek. I definitely will.

Is it possible the car is throwing a code and the ESS tune is "blocking" it?

[IMG]

Ess doesn't block any codes. As Malek suggested, Check your injectors. Maybe one of them is not secured or clipped in properly.

[Malek@MRF]

Originally Posted by W Cole

Thanks for the reply Malek. I definitely will.

Is it possible the car is throwing a code and the ESS tune is "blocking" it?

The ESS tune won't block anything of that sort, even small measly 02 related codes will show up if something minor is not functioning correctly.

A fuel leak is not detectable by OBD-II unless the leak is so severe that fuel pressure is being lost. If your EVAP system is damaged or faulted, you will most certainly get EVAP related codes rather quickly, especially if the EVAP monitor is complete.

I would check your injectors and installation. The fuel could simply be trickling toward the rear of the car or the smell could be pushed toward the rear making it seem like its coming from there.

[W Cole]

Originally Posted by Malek@MRF

The ESS tune won't block anything of that sort, even small measly 02 related codes will show up if something minor is not functioning correctly.

A fuel leak is not detectable by OBD-II unless the leak is so severe that fuel pressure is being lost. If your EVAP system is damaged or faulted, you will most certainly get EVAP related codes rather quickly, especially if the EVAP monitor is complete.

I would check your injectors and installation. The fuel could simply be trickling toward the rear of the car or the smell could be pushed toward the rear making it seem like its coming from there.

Good to know. Thanks

[DLSJ5]

Any update?

Some solid advice here, but I tend to agree with JEllis, the Left Rear, unless you've had recent work done on the fuel system, sounds like the Charcoal Canister. You can quickly check the fuel sender by pulling up the drivers side / left rear pass seat, fold the carpet to the side, unscrew the 4 - 10mm nuts and lift up the thin black lid. Once you get that up you will be able to tell right away if there's a leak there between the sender Hat and gas tank, or the feed line, it will most likely be dirty from the elements, but you will be able to see if any fuel is leaking there, or smell it. If that looks leak free and no smell, then I'm pretty sure it's the Charcoal Canister or one of those lines in that area, which are located very close to the left wheel well.

[W Cole]

Originally Posted by DLSJ5

Any update?

Some solid advice here, but I tend to agree with JEllis, the Left Rear, unless you've had recent work done on the fuel system, sounds like the Charcoal Canister. You can quickly check the fuel sender by pulling up the drivers side / left rear pass seat, fold the carpet to the side, unscrew the 4 - 10mm nuts and lift up the thin black lid. Once you get that up you will be able to tell right away if there's a leak there between the sender Hat and gas tank, or the feed line, it will most likely be dirty from the elements, but you will be able to see if any fuel is leaking there, or smell it. If that looks leak free and no smell, then I'm pretty sure it's the Charcoal Canister or one of those lines in that area, which are located very close to the left wheel well.

The injectors looked good. Haven't had a chance to pull the seats.

I was working on the rear suspension today and it smelled after driving the car only on the left (driver) side.

My car is recently supercharged. Is there some way the boost is causing this?

[DLSJ5]

Originally Posted by W Cole

The injectors looked good. Haven't had a chance to pull the seats.

I was working on the rear suspension today and it smelled after driving the car only on the left (driver) side.

My car is recently supercharged. Is there some way the boost is causing this?

No I don't think it has anything to do with the SC. If you have found no leaks but still smell raw gas fumes in that area, left rear wheel well, then the charcoal canister is the likely culprit, the raw gas fumes in that area, if the charcaol canister isn't capturing them, are pretty potent. JEllis asked in his post, have you ever overfilled your gas tank?

[JEllis]

Yes, the charcoal filter is the easiest answer but the fumes would be stronger from the passenger side. Or, better said, you would probably smell it from the whole rear of the car. Topping off causes the charcoal filter to get wet with gasoline. Once this happens there is no getting rid of the smell without replacement of the whole filter.

If it really is just coming from the drivers side, then it could be the sender/transmitter unit. Its under your rear seat. Pull up the rear seat and look for wetness around the rubber seal. If you don't see any then lift of the seal and look for any leaks underneath.

[DLSJ5]

Originally Posted by JEllis

Yes, the charcoal filter is the easiest answer but the fumes would be stronger from the passenger side. Or, better said, you would probably smell it from the whole rear of the car. Topping off causes the charcoal filter to get wet with gasoline. Once this happens there is no getting rid of the smell without replacement of the whole filter.

If it really is just coming from the drivers side, then it could be the sender/transmitter unit. Its under your rear seat. Pull up the rear seat and look for wetness around the rubber seal. If you don't see any then lift of the seal and look for any leaks underneath.

J, the Charcoal Canister is on the drivers side rear in the E9X, and the exhaust/tube portion of the CC actually sits right in the wheel well behind the liner, that's probably what the smell is, especially if the CC is no longer trapping the fuel vapors. Unless he's had recent work done on his fuel system, or there are visible leaks, it's highly unlikely that it's the sender unit or fuel line leaking under the seat. But that's certainly a possibility, he needs to check that ASAP.

[knevel]

Mine stinks cuz it's catless. It smells like power.

Hope you get it sorted out!

[JEllis]

Originally Posted by DLSJ5

J, the Charcoal Canister is on the drivers side rear in the E9X, and the exhaust/tube portion of the CC actually sits right in the wheel well behind the liner, that's probably what the smell is, especially if the CC is no longer trapping the fuel vapors. Unless he's had recent work done on his fuel system, or there are visible leaks, it's highly unlikely that it's the sender unit or fuel line leaking under the seat. But that's certainly a possibility, he needs to check that ASAP.

Yeah I only mention the sender unit because that is a major failure point, in terms of leaks, for old E36s, that and the pump itself. I doubt its the sender unit as well, the car is too new for that sort of failure.

[MilehighM3]

Access the charcoal canister in the left rear and disconnect the lowest pipe to check for liquid. If gas comes out or the connection is wet, that's definitely the source of the smell. If there is fuel in there it's only a matter of time before the tank vent valve gets damaged and has to be replaced as well.

[W Cole]

Originally Posted by MilehighM3

Access the charcoal canister in the left rear and disconnect the lowest pipe to check for liquid. If gas comes out or the connection is wet, that's definitely the source of the smell. If there is fuel in there it's only a matter of time before the tank vent valve gets damaged and has to be replaced as well.

Do you access this from above by removing the rear seats? Or from under the car?

[MilehighM3]

Originally Posted by W Cole

Do you access this from above by removing the rear seats? Or from under the car?

From under the car. There's a plastic panel behind the left rear wheel that you remove. There's about 6-8 8mm screws you'll pull out to remove the panel.

[W Cole]

Thanks for all the help. I have tomorrow off work so I'll see what I can find.

[pimple]

Google search led me here. Strong fuel smell at driver's rear side.

Don't waste money on a charcoal canister like I did, which is in the passenger's right rear wheel well. Rather, the problem was that the fuel was pooling up on top of the fuel filter, presumably due to a bad fuel filter, which has an integrated fuel pressure regulator if I understand it correctly. The fuel filter is located on the driver's side (i.e., left) side of the fuel tank underneath the back seat. A new fuel filter solved the problem.

I also replaced the fuel pipe that connects at the top of the fuel filter, but I don't think that was necessary. (Did the charcoal canister first, then the fuel pipe, and finally the fuel filter assembly.)

2006 BMW 530i.

[pinoye90]

Originally Posted by pimple

Google search led me here. Strong fuel smell at driver's rear side.

Don't waste money on a charcoal canister like I did, which is in the passenger's right rear wheel well. Rather, the problem was that the fuel was pooling up on top of the fuel filter, presumably due to a bad fuel filter, which has an integrated fuel pressure regulator if I understand it correctly. The fuel filter is located on the driver's side (i.e., left) side of the fuel tank underneath the back seat. A new fuel filter solved the problem.

I also replaced the fuel pipe that connects at the top of the fuel filter, but I don't think that was necessary. (Did the charcoal canister first, then the fuel pipe, and finally the fuel filter assembly.)

2006 BMW 530i.

Yesss!!! I have this same problem ended up almost buying a charcoal canister for no reason. Replaced my dtml pump and the problem never went away. I called my Bmw master mechanic Friend and he told me it’s the fuel sending unit underneath the driver side back seat. The thing to keep in mind, is the smell happening all the time or only during high gas tank levels. If so it’s highly that location leaking or failing👍🏽