Have you drained you gas tank using the fuel pump?

[IronmanE30]

I want to use the fuel pump to empty the gas tank. I used a gear oil plastic hand pump to drain the last one through the top holes in the tank and it was a pain in the ass. I thought that it would be quicker and easier to just use the fuel pump. So I want to disconnect the fuel line at the pressure regulator and pump out of the tank. Any issues that any of you can think of? Anyone tried it?

Cheers,

Jim

[JasonC]

There is a drain plug on the bottom of the tank.

[IronmanE30]

Thanks, I was concerned that only half the tank would drain using the drain plug. But maybe the same thing would happen using the fuel pump. The reason that I want to drain the tank is because I think that there may be some old gas in the tank and I want to start with fresh gas.

Cheers,

Jim

[jlevie]

Whether the tank can be drained via the pump depends on which tank you have (early or late). Early tanks that only have a right side pump & sensor also have a cross over tube between the tanks halves. Those tanks can be emptied via the pump or the drain plug. Late model tanks with dual sensors don't have a cross over tube and rely on a siphon to lift fuel from the left side of the tank into the right side. That siphon is driven by the return fuel flow from the FPR. So a late model tank cannot be fully drained via pump or the drain plug. The left side of the tank has to be pumped out via the sensor opening on that side of the tank.

[IronmanE30]

Whether the tank can be drained via the pump depends on which tank you have (early or late). Early tanks that only have a right side pump & sensor also have a cross over tube between the tanks halves. Those tanks can be emptied via the pump or the drain plug. Late model tanks with dual sensors don't have a cross over tube and rely on a siphon to lift fuel from the left side of the tank into the right side. That siphon is driven by the return fuel flow from the FPR. So a late model tank cannot be fully drained via pump or the drain plug. The left side of the tank has to be pumped out via the sensor opening on that side of the tank.

PERFECT! Thank you, this is the information I was looking for. It is on a 1991 so I can use the drain plug for the passenger side and I will have to go get a better hand pump to work the drivers side of the tank. I was hoping that the fuel injected system used fuel pressure to move the gas from one side of the tank to the other and the fuel pump would be the tricky way to get it done without having to remove the drivers side sending unit.

Cheers,

Jim

[DJB]

Yes, you can drain the tank from the FPR outlet. Even with the later saddle tanks without center tube.

First run the right side tank dry. Reconnect the return line, add a pint of fuel to the tank, then run the pump for a minute or two. That will siphon the fuel from the left side to the right side. You can then finish draining using the FPR outlet.