HELP! STRONG GAS FUMES

[BMW4631]

Help!

I finally located where the strong gas smell is coming from.
It's located under the driver's side back seat, next to the the left fuel sender unit. There is a gas plastic conduit that terminates without any connection at all. Gas fumes are flowing from that opening when the engine is switched ON. When i obstructed the opening with my finger the smell goes away.

Does anyone have an idea of what the pipe is doing and if it's normal not to have anything attached to it?

[ROYinGA]

tank vent hose is not connected to the tank. It goes to the expansion chamber which is located up over the rear axle on the drivers side behind the panels in the wheel well. The picture is for a 5/97 and later car. Earlier is not quite so complex.
http://www.realoem.com/bmw/showparts...57&hg=16&fg=10

[Bmw4631]

Its a late 96, model 97 740i.
I ll try to get back under the car sunday mornin and attempt to trace
back that pipe, it looked like the tube is going to the back driver wheel well
i ll let you know my findings
by the way i had an evap emission code intermittent and the car runs
great with no drivability issue whatsoever...

[BMW4631]

Hi,

it's know confirmed that it's one of the four pipes that come from the expansion tank located in the rear left wheel well. And it's the thickest one of the four. It's probably the vent valve that allows air to enter the tanks to equlize the pressure?

Anyhow that is the pipe that is leaking strong gas fumes constantly when the engine is on. It doesn't have the charcoal canister attached to it... I don't know what to do at this point even after spending much time on the forums...

Can it have something to do with the expansion tank not doing its job?

[ROYinGA]

#7 from the tank to the plastic vapor tank and #8 back to the tank. #13 to the carbon can and #15 to the engine compartment. #15 should hook to a solenod valve near your oil filter and it should have a small hose to the intake manifold/throttle valve assembly. US cars have had the charcoal can all the way back to the mid 70s. You would probably get an emissions signal if the hoses are not hooked up but the car would still run OK. New picture.
http://www.realoem.com/bmw/showparts...95&hg=16&fg=10

[BMW4631]

So you think i should check the connection to those hoses?

[ROYinGA]

if the hoses are not connected. The solenoid valve vents the carbon can to the intake manifold at the instruction from the DME and the collected gas vapors desorb and are burned in the engine.

[BMW4631]

Hi, I checked and it looks like all are tight and sealed.
Can it be then the valve in the expansion tank that allows air into the pressurized system to prevent the tank to implode that could be broken or stuck open and is allowing air to flow in both directions hence the fumes of gas from the vent pipe?
In that case do i need to replace the expansion tank?

[BMW4631]

Little correction, it's the pipe that is coming out of the evaporative canister that is sending out the gas vapor fumes, not the expansion tank like i originally thought it was.

I ll probably change to the new pipe version and perhaps change the canister as the valve inside of it might be defective...

[ROYinGA]

thought the only connections were from the evap tank and to the vent solenoid.

[BMW4631]

I m not 100% sure, i ll have to open to wheel well up this weekend. Furtheremore there is still a possibility that the solenoid isn't doing it's job which is to suck up the fumes and dump them into the engine...

i ll have to spend time on that this week, as the canister is kind of expensive.

[ROYinGA]

with 12 volts and see if you can blow through it to test it.

[claudio512]

Usually it occurs to a hose before fuel regulator... near firewall under the acoustics cover on the engine compartment that is leaking...



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