Fuel tanks uneven, cant seem to figure out, Help

What kind of truck?

 

Yeah, the "modern improved" fuel systems they came out with whereby they figured they could do away with a crossover line. Isn't that just rich, when you are in danger of running out of fuel on the highway, yet have a tank which is right full. I got so frustrated with the same thing you describe, that I did 2 major things, either of which probably by itself would have been sufficient, but I'd had enough. # 1 I went and put the old style crossover line between the tanks (on my truck there is a channel iron running across from tank to tank, so I zip tied it to that). # 2 I went through the agony (yes, no friggin room to work) of putting shut off valves on both suction and return lines on each tank. I can now isolate either tank at will. This way, should my crossover line plug or gel off, I can still "force" the truck to suck only from the full tank, should that situation ever arise again. This new system is one, that, like everything else is just fine as long as it works the way it was when new. It just isn't bullet proof. The problem is there are numerous things which cause it to malfunction, and when you are talking about running out of fuel in the middle of nowhere, that's just bad imo. They should have left it the way it was, or, at the very least, not been so g.d. cheap building these trucks with no valves. (Some might have them, an 07 pete i drove didn't, nor my 04 star.) Hope this helps you. It takes some doing, but it's a surefire cure.

 

The lines need to be the same length, size and routed exactly the same (mirror image left to right). If one has a litle more of a hump or bend, things don't work right. The lines should never be higher than the tee at any point. In order for a dual draw system to work, the return lines need to be submerged and have no leaks in the return lines inside the tanks. I had a retun line inside a tank crack and it drove me nuts. It was cracked about 1/2 way, so everthing worked find with full tanks, but lowered than 1/2, they would not draw equally.

It doesn't take much of a difference in restriction to screw things up. Make sure all lines up to the Tee's are OK and be sure that there are no leaks outside or inside the tanks, and make sure that all the fuel lines are good.

You can add one of these valves to the return side in place of the tee:
http://www.4statetrucks.com/fuel-ta...rs-high-flow-peterbilt-other-models_29770.asp

They have reed valves that help keep the tanks level. When fuel level is lower on one side, you get a little stronger siphon effect and that reed valve will open more than the other, allowing more fuel to return to the tank with the lower fuel level. They make the system a little less sensitive to small restriction differences, but they will not fix a problem, so make sure that all your lines and routing are goof first.

 

Possible frozen or plugged breather on fuel tank have had same problem on more than one kw

 

I don't understand why they'd be like that. Do your tanks stay fairly equal until the level drops below the returns? If they do, I'd say that you need to run them to the bottom of the tanks. Were the tubes or tanks changed at some point? Maybe KW did something different, our Petes and Freightliners all have the return tubes fully submerged.