How do I know which fuel line goes to the engine and which goes to the fuel tank?

Question

I changed my fuel filter for the first time.

I have a 2004 Toyota Tazz 1300. I have installed my new fuel filter. Here it is:

And this is my fuel filter zoomed in:

I have assumed that the tube on the left going down comes from the fuel tank, and the right hand tube over the top goes to the engine. Is this correct?

I ask, and am second guessing myself, because the previous fuel filter was installed opposite to this (the in arrow connected to the top tube, and the out arrow connected to the one going down). Is it safe to assume that the one on top is the engine one, or is there something here I am missing and it should be the other way around?

Answer 1

Follow the fuel lines carefully. It appears that the route of the fuel lines and fuel flow goes:

1. From the tank to the fuel pump on the engine in the upper hose to the pump that appears to come from under the firewall, then
2. To the fuel filter in the lower hose from the pump to the right hand side of the fuel filter, then
3. Thru the filter and out on the left hand side to the short black hose that heads down.

The big question is "where does the short black hose go?" If it leads to the engine, then I'm right and the fuel inlet of the filter should be connected to the long black hose and the outlet should go to the short hose, but if that short hose leads under the vehicle and back to the fuel tank then it is more of a mystery and you'd want to track the upper hose on the fuel pump that appears to also head towards the back of the car. One of those two should lead to the fuel distribution system on the engine. The one that does should be attached to the outlet side of the filter.

Answer 2

From the first picture it appears you have it attached correctly. The one coming up from the side and below would be from the tank. The other one is headed to the engine. Looks like you're golden.