Hi group I need somebody to tell me how the 2 fuel pump operate on a 2001 mercedes-benz c320 V6 MODEL M112 3.2 GASOLINE ENGINE all the gas end up on rhe left side of tank right side empty out. Both the fuel pump run and I recheck the hoses inside that how I found out ride side was empty I put gas in twice about a total of about 6 gallons of fuel. The Fuel Pressure Gauge on the fuel rail read 0 but the bleed line on the Fuel Pressure Gauge showing drops of fuel with alot air when pushing the button in on the Gauge also I have jump the relay plug to get the fuel pumps to run. I check to relay it seem good I think it a wring problem not grounding the relay.
I had the front fuse box out and computer hardness unhook too so I could change the hood cable look like it was going brake soon the fuse box was in the way. What I done it started with the gas tank leaking. had to take out the fuel tank to change it. but couldn't find a used tank anywere. I allready got the fuel pump out the hoses and wring out too because I thought I could find a used tank. So I'd plastic welded the tank for a small hole on the left side not leaking lucky now since I couldn't find a tank. To get the tank out I had major job had to drop rear sub frame, replace the whole exhaust system because it was rusted thought that meant I had to move the oxygen sensors to the new pipes. also change all bushing in rear suspension there were also shot. If I know it needed all of this work and money I should it junk it. please help me with any information that might help thank craig

Hello Craig, i hope someone can help you! well done on all the work you have completed. I did a bit of searching and they call it "saddle tank syndrome". Not a simple system is it, seems to work on a vacuum also, its a real shame you cant find a used tank , especially knowing it has a repaired hole in it.

*double post sorry

i managed to find this thread though https://mbworld.org/forums/c-class-w...y-01-c320.html

There is no 2nd pump.
the main pump and filter need to be in good condition for the system to siphon the fuel back to the right half. Check fuel delivery on return side. 1 litre in 30 sec

It's the same as this.
https://www.ms-motorservice.com/en/t...-tank-modules/

thank you craig