I have a 1985 BMW 528e and I have recently started smelling unburnt fuel when idleing with the windows open. It also takes a few cranks to get it to start but then run ok when it does. Any ideas as to what this could be?

Open the hood and look at all of the fuel lines including the fuel rail where the injectors are. Feel around all of the fittings for a leak. If all of your fuel lines are original, it is time to replace before you go up in flames.

Someone in another post mentioned that the smell could be coming from a leaking in the gas tank fill tubes which is a common problem in older e28's. I think this might be the case since i checked the trunk last night after driving and smelled a faint odor of fuel in there. Is there any way anyone knows of to patch a gas tank without removing it?

Under the carpet in the trunk you will find an access cover to the in-tank fuel pump. Take the cover off and see if any of your fuel lines are leaking there. You could also be getting some fuel smell from the lines that vent the vapor from the fuel neck going into the tank. They run to a box that is in the trunk under the rear parcel shelf.

i get a fuel smell when I completely fill my tank up . could this be a leak in the fill lines?

i get a fuel smell when I completely fill my tank up . could this be a leak in the fill lines?Yes, that could be the problem. In a car this old, nearly all of the fuel handling rubber should need replacement.

We all have a high pressure fuel system compared to carbs of old, that means a leaking line can spray fuel some distance and at unpredictable locations. Gasoline fed fires are not pleasant under any circumstances, deadly in some cases.

There is a vapor canister above the right rear tire, inside the trunk. Check it for cracks, and check the lines going to it.
Good luck

Start the car cold, and as it's idling take a flashlight and look around every nook and cranny of the fuel lines. I had the same problem and one morning I finally found that a clamp to a fuel hose running to an injector had gone bad. Weeks of frustration was cured with a $1 clamp. No more smell. :)