Running on one fuel tank?

My 99 379 has valves on the tanks already don't know if it came with them or not but by shutting off both the suction and return lines you will be able to run one tank with no trouble

 

What he said, just put 2 ball valves on the tank you don't want to use. I cut all my stock fuel lines out and ran all new just to the drivers side tank. Put a "T" in the return port of the driver side. Then a electric pump with a switch on the dash that sucks from the supply port of the passenger tank. If I run the pump when driving I just watch the fuel level.

 

Valves should already be there. Just turn them off. It's not a big job to change the splitter. Also you can fine tune the return by slightly closing the return valve on the tank that is getting more fuel in it. I had an issue with mine not balancing one time and it was a sealing cap from a bottle of fuel conditioner that fell into the tank and was blocking the fuel outlet in the bottom of the tank. Luckily it migrated to the back of the tank by the filler hole so we could see it and fish it out. We were all set to change valves,fuel lines etc. Check the simple things first lol.

 

I know both my fld shakers had factory shutoff valves on them. Two handles under the drivers door. Each handle was connected to a pair of valves. If you pulled the handle it shut off one of the tanks.

 

Some trucks come with valves, many don't. I got tired of having one tank get so full that it was pushing out the overflow while the other side was close to empty. I changed out the splitter equalizer valve, thought I had it solved til it did it again. Breathers not plugged. Got mad, put in an old style crossover line, as well as put ball valves on both suction and return lines. End of trouble. Now I can isolate a tank if I need to. These pressure sensitive equalizer valves are fine as long as they work, but eventually something can happen to cause a pressure differential, and the system goes wonky. That's when you end up with one full tank and one empty tank. And that's just worse than bad, you can "run out of fuel" and airlock your system while having still 100 gallons on the other side. That's why I did what I did. It takes some time and effort to get those valve put in, but, boy was it worth it!

 

I can run on one tank only. From the tank you want to use run a line straight to the primary filter. Put a tee in that line where your factory hoses cross over to the driver's side. Run a line from the tee over to the other tank. Put a gate valve with a round knob in that line so you can adjust it as needed. Mine is open 1/2 of one turn. Then run a line straight from the engine to the tank you are using as a primary tank. You want to draw just enough fuel from the secondary tank to keep it at the same level as the primary tank. It takes a little experimenting to the valve set just right. I did not use a bottom crossover line because of the liability when a fitting gets knocked off by road debris. Been there. Done that.

 

there is something in your tank that is being sucked up once in a while. I would run it down and suck it all out and see. I had the same problem. Was the foil off of a bottle of anti-gel. I preach to deaf I guess. Good ever since.

 

Run your tanks as low as you can and look in them with a bright light at night to see whats in there.

 

I ran with only one tank for almost a year. Actually took the secondary tank off and saved couple hundred pounds. Was not inconveint at all.
Did have to get fuel approx. once per day but I was stoping every evening anyway.