Gas smell

[SIIDEWAYS]

So for the last few years, I'd only been filling up my tank halfway because I rarely drive my garage queen (and thus didn't want the gas going bad in the tank) and because I wanted to keep it light in case some punk in an S14 needed spanking .

But in all seriousness, I decided to finally fill it up all the way yesterday since I've been driving her more regularly lately. And now I'm smelling gas all throughout the garage even though there is no visible leak. Coincidence? Or could I have unintentionally dried up a gasket of some sort by keeping the tank half empty and now with the sudden full tank something is leaking very slowly?

[NoLastName]

Most likely a bad seal on the tank pump or sender unit, or cracked plastic on the pump or sender. Lift up the back seat, remove the two access panels and look underneath. If it's damp at all you have a leak.

[shogun]

Here are the fuel hoses, start checking in the area before/after the fuel filter http://bmwfans.info/parts-catalog/E3...e/fuel_supply/
especially fuel hoses #5 , when I replaced the fuel filter, both were very brittle and I replaced them http://bmwfans.info/parts-catalog/E3...ply/fuel_pipe/
In case you use aftermarket fuel hose, use FPM material, not cheapo NBR.
Also check in engine bay these hoses, http://bmwfans.info/parts-catalog/E3...ration_system/ including fuel tank breather valve/disturbance air valve hoses

[Braymond141]

Passenger side wheel well canister barb(s) is likely cracked.

[Cosmos Kramer]

I’d check around the fuel filter also.

[AJLM34A]

I had this happen about 6 years ago and when I removed the access panel over the drivers side there was some gas residue so I replace the rubber ring. The next fill up, the odor came back. It was the rubber fuel line that goes from the drivers side forward, then down and towards the front of the car.

[expy98]

Same thing on my 98 sedan after each fill up... both hoses under the rear seat bottom cushion were cracked enough to smell but not dripping. Was able to trim the cracked ends about 1/4" and put them back, there's not much slack in those hoses. Also did the same for one of the hoses to the expansion tank, a bit of a PITA to remove
the tank and put back without breaking it. Expansion tank survived but those plastic nipples nfg... Smell no more...

[SIIDEWAYS]

So I backed the car out of the garage and found a tiny little puddle, actually more like a spitful, of gas on the garage floor. So there is definitely a small and slow leak somewhere. Or maybe it was excess gas that somehow dripped its way down some hoses, etc.? After all, I did top off the tank a little even after it clicked full once (trying to round it off to the nearest dollar - yes I'm OCD like that). But after I took her out for a spirited drive to burn some gas and got it down to about 7/8th full, I parked back in the garage and checked on it a couple hours later - no gas on the floor or gas smell for that matter. So it looks like it was only an issue when the tank was full. Any ideas?

Plus, I removed the back seat per some of the feedback on this thread, but couldn't find any access panels, much less figure out how to remove them.

[AJLM34A]

Under the back seat, seat bottom on the left and right of the car.

Screen Shot 2020-03-16 at 6.01.53 PM.jpg

[bmwstephen]

OP did you ever solve for this? I am thinking I have the same issue but no visible drips or cracks on my end. only happens after a fill up to full tank and goes away after I went through half a tank

[blckstrm]

I wish I had some advice - mine was the cracked barb Brett suggested.

But my E32 is doing this now and it's the same as described - only when the tank is freshly 100% full. So I've been conveniently ignoring it for a year.

[SIIDEWAYS]

OP did you ever solve for this? I am thinking I have the same issue but no visible drips or cracks on my end. only happens after a fill up to full tank and goes away after I went through half a tank

Sorry, just saw this. But like blckstrm, I just rarely fill it up 100% and simply haven't done so again ever since - problem solved! lol

No, but in all seriousness, I bought a new seal for the sender unit as someone suggested earlier, just haven't gotten around to actually replacing it yet.

[mgambini]

I'm not sure whether it was one of my BMWs but I had the same problem on a car. Pulled the tank out and found that there were some rusted pinholes in the top of the tank because the tank had some indentations that trapped water. Gas never leaked down, just a small amount would wet the top of the tank and cause the smell. It was repaired with a gas tank repair kit.

[RBNetEngr]

We have an F30 328i, and if the tank is filled completely, there is a strong fuel smell. In searching the Internet, I found that the tank on that vehicle only has one top opening for the pump and level sending unit, but the tank actually was made with TWO openings, and BMW puts a large plastic ‘plate’ on this other opening. And over time, the seal between the plate and the tank leaks, allowing vapors to escape. The only repair is to seal the edge of the plate, but to do so, the tank needs to be removed. Or else, replace the tank.

So, maybe that E32 has a similar issue?


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[pbonsalb]

I have to fix this on my 99 M3. It’s been an issue for a few years so I try to not fill the tank completely. A couple of years ago, I checked the hoses on top and the nipple in the wheel well and those were fine. Might replace the pump/sending unit seal next. Will also check the metal fittings for pinhole leaks. I have been in the tank a few times (new stock pump, walbro 255, deatschwork dw300 over the years as my forced induction needs went up).

[gsanvi]

I also had this problem and it was driving me nuts. Replaced seals for the fuel pump and fuel sending unit, still felt the smell. I couldn't pin it down for a long time. In the end it turned out that the one of the rubber lines crimped to the blue plastic lines on top of the fuel tank was only so slightly cracked. Replaced that and boom, no smell anymore.

[importbanana]

Was it a line that was connected to the pump or sending unit or somewhere else? Which line exactly? Can you show in a parts drawing?

[gsanvi]

This is the part number: 16111181361

It was the one connected to the pump. However the rubber on all of those lines was dry and decomposing, so I replaced all of them just in case. By replace I mean I took it to a shop that crimped new rubber lines to the blue plastic ones, which were in good shape.

[NeilM]

I'm not sure whether it was one of my BMWs but I had the same problem on a car. Pulled the tank out and found that there were some rusted pinholes in the top of the tank because the tank had some indentations that trapped water. Gas never leaked down, just a small amount would wet the top of the tank and cause the smell. It was repaired with a gas tank repair kit.

E36 fuel tanks are plastic.

Neil

[pbonsalb]

Isn’t there a metal plate on top with the tight angle nipples the hoses attach to? Been a while since I looked. Maybe it is all plastic.

[NeilM]

Isn’t there a metal plate on top with the tight angle nipples the hoses attach to? Been a while since I looked. Maybe it is all plastic.

Nope: the fuel pump and level sensors seal the top openings of the tank, and they're plastic. Above those there's a metal cover for each access hole under the rear seat base, but those are dry. Well, unless something else leaks.

Neil

[scoobiedoo2029]

i have a dealer recall sticker under my fuel door for a evap fix. cars a 1996 production sedan, im not sure what the recall was at the moment. but somewhere in the m3 production there is a evap recall. or i just have some wierd bmw dealer sticker with numbers on it under my fuel door.

i also just noticed only 1 steel hard line under the car has some corrosion on it. the fuel feel line wasn't the other brake lines look fine as well. i believe there is an evap line running in this location???? dosnt it feed the wierd donut thing under the spare tire?? im only just finding this and searching but i could see a evap line corroding a steel hardline in 25 years.



surprisingly cars dont seem to light fuel on fire very easily. i touched a fuel pressure regulator on an m30 once, and the oring instantly disintegrated and sprayed gas everywhere. a hot exhaust was not enough to light it up thankfully.

[Braymond141]

Fuel EVAP line is blue and is plastic. The two larger metal hard lines are Fuel supply and return lines. The two smaller metal hard lines are brakes.

[Grey Phox]

I had a very similar problem with my car back in 2020. No visible leaks with the occasional start, couldn't track it down but I had a strong gas smell and this was while it was outside. Eventually I crawled under while leaving it running one day and found one of the fuel hardlines was leaking in the area in front of the driver side rear wheel.

Since i needed a laundry list of things and no time, I had a shop do it. As far as that went they checked it and it indeed was the problem. Real pain in the ass to track down and it was right in front of my face the whole time.

To me its crazy to think a car that has lived its life in Cali could have that happen, but anything is possible I guess. My car doesn't get driven at all in the winter months at least since I bought it in 2008.