Gas fumes in the passenger compartment?

Technical

cgshawaii@netscape.netwrote:
Scott there are probably a dozen common places to look for gas fumes, I'll start naming some of them.

1. The sender may be loose at the tank. Remove the right trunk floor board when you have a full tank of gas, vigorously rock the car to check. Should not be any wetness on top the tank. The sender is a twist-on, use two crossed screwdrivers on it.
2. Check for bad/cracked fuel hoses. The old style hose with braided cotton outside gets (very) brittle after a while. Usually it will weaken just at the nipple of whatever it's connected to. Replace with new hose, not the same type.

3. There is a small plastic sleeve on the fuel sender nipple where the gas line connects. Over time it can get brittle, crack and leak. It's frequently discarded with old hose if you don't know it's there; if you use new rubber hose and a hose clamp you probably won't need it. Anyway, the rock-with-a-full-tank technique usually finds this problem.

4. Check the evaporative line from the gas tank filler neck to the evaporative canister over the right rear wheel. Check the plastic canister and the blue plastic line which runs forward also, they must all be air- and fuel-tight.

5. Notwithstanding that gas in the trunk is a bad thing, you'll smell gas if the trunk lid gasket does not adequately seal the trunk. Climb in, have someone you trust close the lid, look for daylight along the trunk/gasket joint. The gasket must firmly seal all the way around or trunk fumes will be drawn into the passenger compartment. Alternatively, try to slide a piece of paper between the gasket and trunk lid, all the way around; should be snug all the way around. This is particularly an issue if you've been rear-ended.

6. Check your gas tank for leaks, especially at the welded seam, and under it where BMW stupidly used a water-retaining foam strip where the tank rests on the body. Eastwood, POR-15 and others make tank sealing compounds. Run the tank to nearly empty before you take the tank out, and replace that damn foam rubber with something non-absorptive.

7. Check the rubber filler boot between the gas cap and tank neck, also that the clamp is adequately snug on the tank neck.

8. You have to use the correct gas cap, there are two kinds, one vented, one non-vented. One is marked Ohne Luftung, I think this is the non-vented (?).

Now to the front of the car.

9. Check that the evaporative line is connected to the charcoal filter. Most of the filters have long since rusted away and are gone; in this case connect the line to the air filter housing.
10. The Zenith carbs seem to commonly leak a little, but this won't get into the passenger compartment unless the seal at the top of the gutter (wherein lives the fan intake, wiper assembly etc.) is leaking. Check the seal, a part from another Bimmer may be an available inexpensive replacement.

11. Fuel lines must be checked and replaced as needed: fuel pump suction, fuel pump to carbs, fuel return to tank if injected.

12. What everyone else said, if I haven't found it.

--

Charlie BMW CCHawaii

--- Brettwrote:

Scott, I had this very problem (1971 3.0CS). the problem was that the twist-on fuel/sender unit had come loose and so fuel was leaking past it and resting on the top of the trunk which would fill the passenger compartment with fumes. so check that part and make sure its tight and not leaking.

bretthttp://www.oldbmw.com

Firebone2@aol.comwrote:

Hello,

My name is Scott Hartman and I have a 1967 2000cs that has been in the family since it was new. I restored it about 10 years ago and it is a great little car! I've got a question that someone may be able to answer for me... the car has always suffered from gas fumes in the driver/passenger compartment... believe that the fumes are coming in from the trunk of the car rather than from the front end. I've heard in the past that this is a common problem for this model. Is there anything that I can do to fix this? It gets to be over powering after a 1/2 hour or so!

Thanks very much, Scott Hartman 20 Highland Terrace Stafford Springs, CT 06076 617 480-1229
      
      