Troubleshooting the Smell of Gas Fumes

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Question:

My 73 trunk smells like gas – not overpowering but enough to be noticed when the lid is opened. Is the small plastic vent line that penetrates the filler tube routed outside the car? All hose clamps are present, hoses look like they have been replaced and the pickup plate screws are secure to the tank. Any ideas?


The best solution to solving gas smell is a process of elimination.

In the photo below, the red arrow shows where the fuel pipe exits the trunk on most 2002s built from 1968-1973. We say some, because it’s not exactly clear if some USA round tail light cars had the later model charcoal vapor container which were mounted above the right rear wheel housing in the trunk.

If you have a bracket above your right rear wheel housing mounted to the package tray, chances are your tank vents to it instead. The 73 2002tii in the USA was a crossover year model which has some variations between old and new because of engineering changes which occured during that build year in preparation for the later 1974-1976 cars.


CHECK THE FUEL TANK VENT LINE

The red arrow below shows where on the early cars it vented through the floor to the exterior of the car.


On cars with the grey plastic charcoal vent container, the line connects from the rubber fuel neck inside the trunk and follows along the wheel housing to vapor canister.

CHECK FOR RUST


The 2002 fuel tank is made of two pieces of steel put together. They are notorious for rust right at the seams where it was put together because of a foam seal underneath the tank which the factory used to stop vibration. This seal was porous and held water, so the rusted severely around the tank in climates where moisture was common. This rust can lead to severe structural integrity problems.

PERMANENT CURE

Most 2002 fuel tanks are no longer available and if they are run more than $600 new. At the time of this writing, 2002tii fuel tanks are no longer available.

It is a good idea if you plan to keep your car and make it reliable is to put all fuel tank fume and leak mysteries a thing of the past.

  • Drain the fuel from the tank itself from the car. There is a small allen head drain plug near the bottom front of the tank under the car which makes it easier.
  • Remove the tank (5 black arrows in photo above). Check for rust on the car where the tank sits inside the trunk and repair if necessary.
  • If you have rust, likely you have tank edge separation. Check the edges of the tank closely for problems.
  • Seal your tank with a proven fuel tank sealer, such as POR-15 or Eastwood makes. Follow their directions.
  • Have your fuel tank boiled out by a radiator shop. The 02 tanks are small enough most shops (unless environmental laws prevent it) will do this for you.
  • Once the inside is done, the edges are next. POR-15’s putty can be used to seal edges where the metal has begun to separate. JB Weld can also be used for this also.
  • Use a high quality undercoating such as 3M in a spray for the underside of the tank, and a good rust preventative black paint on top.
  • Replace your fuel lines with genuine BMW high pressure fuel line materials. They are cheap insurance against fire and clogged fuel filters which can occur after 30 year old hoses have not been replaced.
  • Mount back in your trunk with Stainless Steel fasteners instead of the original Zinc type to prevent further rust issues (See black arrows above)
  • Last, check your trunk seal and make sure it’s in good repair.

Another note… If you have speakers in your trunk, they also may be pumping the fumes into your car also, however finding and curing the leaks and the source of the fumes normally rids your car of future smells.

Last update: 2007-08-14 19:09
Author: The Tii Register

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