My newly acquired project car started making a loud buzzing sound due to the main electric pump working hard. This occurred most often when the tank was 1/3 full and once the car died when going hard around a big sweeper. The first plan was to check the tank transfer pump. Too my surprise, my euro e30 had no transfer pump but just a plain all plastic float assembly. I made a trip to the junkyard only to find that several depth sizes were made. I installed the metal float assembly with fuel pump and replace the main pump for good measure. Make sure you get the connectors for the pump. The gas sender connector is different too. I was told that euro models did not have a inside fuel transfer pump due to Europe's superior fuel formulation.