Can't pull fuel from rear tank

[NTOLERANCE]

I can only pull fuel from the front tank on my van. When I'm the rear tank the fuel filter light comes on and the truck starts to miss. As I switch back to the front tank there must be air in the lines as it takes some time for the engine to even out - it still misses for a bit. I'm assuming whatever is in the rear tank has broken off high enough not to reach fuel. But I'm curious why the fuel filter light comes on.

Running on diesel here not who.

Any thoughts ? Could the fsv be at fault sucking from the return line?

 

[tbrumm]

I would suspect a problem with the fuel switching valve. The filter light coming on is indicating a restriction (which would normally be a plugged filter). What might be happening is when you try to switch tanks, the fsv is moving part of the way to make the switch to other tank and then gets stuck. So, with the valve not moving fully into the correct position, it now is restricting the fuel flow and the filter light comes on. Then you switch back and the valve can move back to its original position okay, but it takes a while for the fuel to get to full flow again and that is why the truck misses for a while and then clears up. There may be some debris in the fsv causing this problem. You can drill out the rivets on the fsv and take it apart and clean it. Replace the plastic clips that hold the fuel lines hoses on it too. Of course, inspect the hoses carefully to - they could be weathered and cracked. There have been a few threads lately on this very subject, so search a bit and you will probably find the thread with instructions on taking the fsv apart.

 

[79jasper]

Pickups probably broke off and sent junk into the lines.
Here's what I would do: pull the selector valve and clean it like mentioned above. Drop both tanks to check/fix the pickups and clean the tanks. Then take the feed and return line off at the front of the van and blow them out with air. Do this with all lines hooked up and the selector valve in place. Blow through it, then turn the key on and flip the switch and do it again.
Oh also replace the orings in the quick disconnects on the selector valve.
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[NTOLERANCE]

I've had the pick ups come apart and plug the fsv before on my pick up. Never had the light come on.

I'll pull the fsv apart and see what's in it. Then on to the tank.

I picked up a folding rear bed finally so I can install my onboard in the cab fuel tank for my who tank. Good time to cinch everything up.


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[NTOLERANCE]

Finally pulled the tank down a few weeks ago. Fsv had some stuff in it. But really the rear tank sump was plugged. Couldn't pull any thing through it. Tried to blow it out. Couldn't. Dropped the tank and during that process the piece that was blocking the line came dislodged so I still don't know what plugged it. But there was enough stuff inside there to do the job. Oddly enough my flat and sender seems functional. Gage still doesn't work

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[icanfixall]

Man you sure found some crap in that tank. All looks like the shower head fell apart. Just add about 3 inches of rubber 3/8 hose and 2 clamps to that line and all will be fine again.