Actually, if the return line is kinked and blocked, it could cause a problem. I am speaking from experience with my Dodge products, but I have a suspicion most other brands are the same. In my 1988 Grand Caravan, I had to replace the gas tank due to rust and was trying to understand how the system worked. The pump and pickup screen sit in a bowl welded at the center of the tank. That is so about a quart of fuel will not run away from the pickup when you go around a corner. If it did that when the fuel level was low, it would stall at every corner. That part I understand, as well as when filling with gas, the filler tube is shaped to dump the gas into that bowl. What I could not figure out is what pumps gas into that bowl while you are driving.
Turns out there was a real nice description in the service manual. The fuel coming back in the return line rushes past a port that creates a venturi action, and that picks up more gas from the tank to keep the bowl full. I scratched my head for a long time, and I am still not entirely convinced, but it does seem to work.
As a point of interest, I have a similar setup in a 1994 Grand Voyager, but after running out of gas, (on purpose), I found that one appears to not dump the gas into that bowl very well. I have to put in almost five gallons, (quarter tank), to get it up high enough to spill into the bowl before the engine will start. Once started, it will keep the bowl full all the way down to "empty".
If my story is right, you should not have this problem if the tank is over about half full. Keep in mind though you have a fuel pressure regulator on the engine, and the excess fuel has to be able to flow back to the tank. If the return line is blocked, fuel pressure can go too high and cause running problems from an excessively rich mixture.
Tuesday, June 14th, 2016 AT 6:58 PM