c280 Gas Tank

[dstorey]

Does anyone know how the gas tank is configured. I have need to drain the tank. I attached a fuel hose to the output side of the fuel filter and put a jumper wire across the fuel pump relay socket. It pumped 4-5 gallons and stopped pumping. Guage showed 3/4 full. I initially thought strainer in tank was plugged. I tried blowing back thru it and it was not plugged. I was able to remove the strainer with no loss of fuel and it was fine. Put it all back together and put 1/2 gal back in the tank and it started and ran ok. Thinking I had actually emptied the tank, and the gage was wrong I filled it and it only took 5-6 gal!

This leads me to the conclusion that there must be some baffle in the tank, possibly a safety feature. How does the gas get by this in normal driving? Any comments will be appreciated!

[porkface]

imagine 2 kidneys-1 behind the driver, the other behind the passenger. there's a connection over the driveshaft where the fuel transfers by way of a suction pump from the lh side, return from the engine, to the rh side, where the filler and main fuel pump is. there are 2 sending units and the gauge on the dash averages them. 1 way to drain the tank is to pull both senders, but it's tricky unless you have the special tool or and adjustable pin wrench with the right diameter pins. good luck, chuck.

[dstorey]

Thanks. Looking at the picture with the manual, I see how the tank is. What I have is the pump pickup on the lh side with a strainer. There is one pump that sends fuel to the engine. ( The book shows some 2 pump configurations). My pump has a smaller second line on the same end of the pump as the larger line going to the strainer that may go to the other side of the tank. Is that to draw fuel from that side? If not, where is the suction pump that you describe?

How this all started is that I was on a trip and may have gotten some dirty fuel. It was missing badly, and I had it towed. I replaced the filter (when I blew back thru it there was dirt) and it ran fine for maybe a week and then started missing again. When I first start it, it runs smooth for maybe 3 min and then goes to missing. I was assuming it was not missing because it was on cold start. Then I thought maybe the strainer was plugged.

I put a gage on the rail and it shows 50 psi at idle but it is missing. Based on the fact that it was ok for awhile with the new filter it still seems like a fuel problem

[porkface]

the suction pump is the fuel lines in the tank that go from the drivers to the pass. side. note-i said is the lines, not in the lines. good luck, chuck.

[dstorey]

How is this pump in the lines powered? Could contamination plug it!

[porkface]

it is not powered, it's a siphon. the movement of fuel creates the siphon that transfers fuel from the lh to the rh side. i said, it's not in the lines, it is the lines. good luck, chuck.