The answer is yes, and I'll identify the point to start at.
Boboquack's solution is great, but I wanted a constructive proof.
This problem is asking about the partial sum of a series. If we define $f_i$ as the fuel at point $i$ and $d_i$ as the amount of fuel we'll burn driving between point $i$ and point $i+1$, then the fuel left in our tank at point $i$, starting from point $0$, is the partial sum:
$$
Y_j = \sum_{j=0}^{i-1} f_j - x_j
$$
There are $n$ points, and $Y_n = 0$ because our fuel sums to 1 liter and our lap would consume a liter of fuel. $Y_0 = 0$ because it's the sum of $0$ to $0$.
We want to know if there is an intermediate point $k$ such that if we started our sum at $k$, wrapped it around at $n-1$ to go back to point $0$ and got back to $k$, every element in that sum (call that sum $S^k_j$) would be non-negative. i.e. if $\forall j S^k_j \geq 0$
We need $S^k_j$ in a simple form, so we'll first add elements between $k$ and any other point $j \geq k$.
This is simply $S^k_j = Y_j - Y_k, \forall j \geq k$.
The more difficult sum is when we start at point $k$, go past all points, and start the sum again at the beginning.
The sum between $k$ and $n$ is $Y_n - Y_k$. The sum between $0$ and $j$ is $Y_j - Y_0$. Adding these together, we get $Y_n - Y_k + Y_j - Y_0$. But both $Y_n$ and $Y_0$ are zero, giving us $S^k_j = Y_j - Y_k, \forall j < k$
Combining these two, we get a simple equation:
$S^k_j = Y_j - Y_k, \forall j$.
Now we can restate the riddle as: can we ensure this quantity is always non-negative?
Sure: if we start at point $k$ and $Y_k$ is the smallest $Y_i$, we will always make it around the circle.
This analysis can be done with integrals and continuous gas cans, with the same result. I actually did that first because integrals are more fun than series summations.