E30 Hard to diagnose fuel smell in cabin after filling up:details below

[dw44240]

Ok Gear heads and enthusiasts,

I think i'm both.
I had to have a new tank installed because the neck rusted away in areas with raw fuel leak.
No fuel smells inside the cabin prior to the new tank install.

Now after the install I noticed the fuel smell with the next fill up.
So I removed the rear seat and discovered one obvious problem area: the vent hose to the filler neck from the fuel pump cover
was severed by the shop that did the tank install ( no, I don't want to go back to them) so I bought an oe hose and installed it,
no easy task on a 28 year old car. I thought for sure this was it.
No such luck.
So using the nose technique, the cover plate of the fuel pump had a noticeable fresh gasoline smell, so I saw two gaskets for the pump, one for the pump and one for the sender, I installed new bmw ones. At that point the tank was about two thirds full. Drove about 200 miles with intermittent partial fills of 5 gallons and 6 gallons. No smell even with the windows and sun roof open.
I thought that might have done it.
But I knew I had to test the full fill, so I put in 13.8 gallons. Immediately upon leaving the station I detected the smell.
Had to stop at the hospital for a visit, about a 5 miles, and upon parking, noticed raw gasoline dripping from the passenger side, about 18inches ahead of the wheel well/rocker intersection. Not a lot but a drip drip drip. Please note, It appears that the fumes are drawn inside the cabin when the windows are open when the tank is nearly full. This dissipates after consuming 5 gallons, which if the car took 13.8 gallons as full, then minus 5 gallons leaves us with roughly 8 gallons, assuming about 25 mpg. NOTE: my gas gauge no longer works.
If reserve is 2 gallons, then the tank can have 10 gallons without causing the smell inside.

I am asking any of the forum for a been there and did this and it fixed it question for help.

Thanks to all for your attention and help.

Best regards,

DW44240

[bmwdirtracer]

The answer is easy: fill the tank, and find out the spot where the gas is leaking from. If you can't see it from underneath the car, pull the rear seat, and look at the hoses and the top of the tank. If you still can't see it, you're going to have to drop the tank again.

You have a liquid drip - therefore this is the source of your smell. Follow the drip.

[dw44240]

I agree with you on the tracing that liquid gasoline. I have examined the top and nothing aside from my latest repairs with hoses and gaskets sticks out. There must be an aspect of the tank that I’m overlooking. The fact that the gas line’s inline filter is on the driver’s side and the leak drip is on the passenger side is what’s baffling my thinking. Is there a line on that side and for what?
Charcoal canister? line?
Some of the lines from the expansion? tank were snipped nearly 3 decades ago before my 20 years ownership.
Any clues on line routing / purpose will be helpful in my sorting.

Thanks,

DW44240

The answer is easy: fill the tank, and find out the spot where the gas is leaking from. If you can't see it from underneath the car, pull the rear seat, and look at the hoses and the top of the tank. If you still can't see it, you're going to have to drop the tank again.

You have a liquid drip - therefore this is the source of your smell. Follow the drip.

[bmwdirtracer]

http://www.realoem.com/bmw/enUS/show...diagId=16_0303

http://www.realoem.com/bmw/enUS/show...diagId=16_0107

Sorry, I can't do any better than these two diagrams.

[dw44240]

BMWDIRTRACER,
Those diagrams, especially diagram 0107, shows a discrepancy with my filler neck.
I'll explain:

I replaced hose - #5 and connected it to the metal pipe coming off the filler neck.
Hose #3 coming from the expansion tank - looks like it goes into a Tee connector with hose #5's small diameter tube on the filler neck. My filler neck is missing that small Tee tube shown below.

You can bet I will check this out tomorrow,

I now think that I might have missed the deletion of that Tee, namely, the removal of the Tee portion on that connector pipe for hose# 5.
And if it is open to the air, then fill-up fuel could travel up hose #5 and spill out where the Tee once was.
Spilling out onto the hose#5 and gravity taking it back down hose #5 and dribbling down the tank and nearby pathways.

I'll let you know what I find and also research with our BMW dealer on the possibility of that Tee.

Thanks very much for this diagram.

Best regards,


DW44240

http://www.realoem.com/bmw/enUS/show...diagId=16_0303

http://www.realoem.com/bmw/enUS/show...diagId=16_0107

Sorry, I can't do any better than these two diagrams.

[dw44240]

Update on filler neck design and fuel pump inside:
My car's filler neck does not have the Tee connection on the #5 vent hose tube.
Also I determined that the expansion tank has two lines(black plastic ) connected to it that are routed to the fuel pump flange area on the top of the tank.
So will be investigating for other culprits, such as the line that goes to the charcoal canister.
Looks to be a process of elimination and I don't have a lift - this will take awhile.

Thanks for your help.

Two heads are better than one on murky issues like this,


DW44240

[88Emmy]

Found your thread because I’m about to start this exact same process... Did you end up having to drop your tank?

Thanks!