Ok, here's the deal. I got a 1990 740 GLE non-turbo and I'm having this weird issue that as soon as the car reaches half a tank of gas it starts acting like it is out of gas and as soon as it goes below half a tank it will shut down and not start until I put gas on it. the funny thing is that it has gas on it, a half tank to be exact and still it won't start if it has less than half a tank. What can be causing this ? Otherwise the car works like a champ until it reaches half a tank.

 

I believe you have the B234 motor. 16v. It's a little different but the fuel issue should hold. you have either bad in tank pump, or the hose lifting the gas from the tank is split. Either way, the fuel pump/sender assembly have to come out. You can do it, but it's challenging and a little messy.