'76 BMW 02 Fuel Line

[jstoewer]

Hello. I have been restoring my BMW 2002 from parts in boxes. I have it running but when the RPM's go up, fuel pours out of a second fuel line that comes out of the top of the gas tank. The fuel line passes through the firewall. I believe it is an expansion line. Should this be connected to the main fuel line or the carburator? I appreciate any suggestions. Thanks.

[02for2]

The '76 has a fuel vapor recovery system. This allows fumes to collect via clear nylon tubing from the fuel tank and filler neck to a white placstic collecting box which is mounted under the rear parcel shelf in the trunk on the P-side.

These fuems are routed via lines to the carbon cannister under the hood and then to the air cleaner to be drawn into the carb and burned off rather than venting to atmosphere.

If your collector is missing, or not hung higher than the fuel hoses, liquid fuel could conceivably be drawn in and leak.

Cheers!

[jimk]

I have it running but when the RPM's go up, fuel pours out of a second fuel line that comes out of the top of the gas tank.

You should not have the vent line connected to the fuel tank proper, but as was stated above, to the filler neck rubber boot nozzle. The nozzle on the tank originally was connected to a fuel return line from a valve near the carburetor. This valve may or may not be on your car. If it has been fit with a Weber, the valve won't be there. The return line is not used then. The return line is the one that runs under the car to the tank and should connect to the extra nozzle on the tank.

[Jerzy]

#19 is the plastic vapor recovery tank that should be mounted in the trunk. (It's not as big as the drawing shows.)

#18 is the line that I think you are saying that the fuel comes out of.

#17 is the charcoal canister that the car had originally

#22 is the fuel return line - often disconnected by now.

#25 is the fuel return valve - often missing.

Are you running the mechanical fuel pump (#24) or has an electric pump been added? If the car has an electric pump, you may be running at too high a pressure. Post some pictures if you can. The electric pump is usually mounted under the car, above the rear axle.

[jstoewer]

Thanks for the information. From your diagram, the #22 line is the one in question. I do not have the #25 valve anymore, so I will just remove and cap that line. The vapor tube from the filler neck is still in place.

[Jerzy]

Some people have used the return line to supply fuel.

For factory correct plumbing, compare this photo to the plumbing drawing in the above post -

[M3M3]

kinda sounds like op is using the wrong line as the feed line and has left the proper feed line open in engine compt. dangerous!

[jstoewer]

Interesting, It looks like I have the fuel return line being used as the main line, which is connected to a electric fuel pump in the engine bay along with a fuel pressure regulator, dialed into 3 psi. The other line that comes thru the fire wall is open ended and is the one that spews gas when I rev it up. I will switch them and see what happens. Thanks.