How does it work? (fuel tank)

[mdrainville@xxxxxxxxxxx]

I always been curious on how the fuel in the gas tank (E30) was managed
considering the fact that the shape of the tank is like two small tank,
left side and right side, joined together with a kind of bridge at the top
of the two sections.

Last week end I removed the tank to have a leak fixed, and at the same time
removed the fuel pump cover and took a look inside to have the answer.
Well, no answer came to me but  more questions.  The way the plumbing is
done is like this:
The filler neck is on the right side. When you fill the tank past 75% or
so, fuel goes on the left side by the bridge.  The fuel pump is on the
right side and push fuel to the filter, then to the engine. The excess fuel
coming back goes in the tank on the left side BUT that fitting doesn't
connect inside the left side. There is a steel tube inside the left side,
routed to the right side by the bridge. So the fuel is pumped from the
right side and comes back to the right side.  What happens to the fuel on
the left side???  It seems to me that it is never used.

On older E30, there was  a transfer pump in the tank (right side) , then a
fuel pump (externally mounted). But my E30 (1991) has only a fuel pump that
is positionned where the transfer pump was on older E30, in the fuel tank
(right side).

Also, there are two fuel level sensor, one is on the right side with the
fuel pump, the other one is on the left side.

Can someone explain to me how the fuel on the left side is managed?

Thanks

Michel Drainville
91 318ic

------------------------------