my mercedese Benz C220 1995 model automatic runs out of fuel when the gauge reaches half tank from full. When you empty it and put in less than full tank, it uses some fuel and the rest stores it in the second chamber of the tank. I have tried to check the tank and found that there is fuel in one chamber of the tank and the other where pump is, is empty. It is not getting fuel from the second chamber 0f the tank. What can i do?

edward Kardinal, April 2010

Excerpt from the MB Owners Forum:
"It really is a fool of a system. Fuel is transfered from the "filler cap" half of the tank to the other by means of a syphon system transfering fuel over the "Hump", provided by MB for the benefit of the prop.shaft. Fuel is taken out of the non fillercap side by the lift pump (or in the case of the C220 by the injector pump). The surplus is returned from the pump/pumps back to the filler cap side of the tank. The two fuel gauge sender units are needed to give a reasonable guess at what is actually in the total tank (there is probably an integrator built into the ECU).
How do I know? Well I had to replace both the injector pump and the tank on my C220 for this problem and we cut the old tank up to see what was going on. It was a leaking pipe within."

http://forums.mercedesclub.org.uk/showthread.php?t=12494&highlight=c220+fuel+tank

ChicksFan, April 2010