BACK TO BASICS: the fuel "crossover" line:

The fuel crossover line comes from years ago, when trucks would only pull fuel from one tank, thus the fuel would flow from the other tank to keep the tanks equalized. Some of the newer trucks pull fuel from both tanks and dont even have a crossover line.

 

These systems are called top draw. The draw from both tanks, to a "T" in the middle. They also have a "T" on the return line.

I believe I read somewhere the return lines have a tube that goes to the bottom of the tank. So if you fill only one tank, the tank with the most back pressure will have the least amount of fuel return to that tank, until the other tank has "levelled out".

I have yet to receive proof on this ,for I can never fit my head in the fuel tank to look.

One reason I believe they went to top draw is, if you happen to rip off the cross over line, you may loose a good bunch of fuel, causing a safety hazard.

With the cross over lines, they usually only draw from one tank. So if the taps are closed at the bottom of the tanks, you will find yourself running out of fuel, with one tank still full.

 

Cool, I could never put how that worked together into my head until you just explained it. Thank Ya. If you ever figure out where you read that I would love to read it too if possible.

 

I think I googled top draw fuel systems.

my interest was peaked after we picked up a truck at one of our locations. I t would not start for nothing. Fuel gauge read full. We finally checked the tanks. One was full, one was bone dry. We put a few cans of fuel in, and away it went.

In looking in and around the truck, I found out it had no cross over lines, henceforth the google check.

 

I could be wrong about the return. I think I found the articles.

http://www.norgren.com/document_resources/EN/Return Flow Splitter Troubleshooting.pdf

 

http://www.norgren.com/document_resources/EN/Return Flow Splitter Installation.pdf

So this is the article that explains it. I was wrong. Sorry!!

 

I learned a lot from both links thank you. Would be nice if we could stick our heads down in there, and take a look around wouldn't it lol.

I suspect my fuel system is picking up air from time to time. One of these days I will take the time to pull the pickup system from both of my tanks and see whats what. I may even go as far as to dump my Davco, and add a FASS or AirDog.

 

Just do not smoke while you are doing it. haha