I bought this truck with the rear tank being inoperative. So i yanked it out couple weeks back.
The tank and pump were like one big tub of gross varnished gas in a taffy kinda way.....
i tied off the two lines going to the pump with ti wraps(kinked them actually) and have ordered a new tank and a pump and a new fill tube. Is there a junction somewhere for the two lines. It appears that the switch just turns on the fuel tank requested by the operator. Is there some other solenoid or are there other things i need to consider in this effort.
thanks for any insight......
rich.

 

After you replace the tank with the parts that you have ordered, run it for a bit, then replace the fuel filter. Run it on the rear tank only for about a day or two, then replace the filter again, then you're pretty much done. I did the same thing a while back.

 

I'm not sure of the set-up on a 91, but on my 88 there's a selector valve with 6 hose connections on it (two in the front and four in the rear). It's located near the fuel filter and in-line fuel pump in my frame rail. I just added the midship tank last week that was removed by a previous owner.

 

Wart..
I was thinking there was a relay or manifold somewhere. Otherwise the fuel could be rerouted back to the wrong tank. On the 91 there are in tank fuel pumps. Don't think there's an inline rail mounted one.
Rich

 

Yes there is a "T" connection on each the supply and return lines.
That is the way it works.
No there is not.

Here is a diagram of your fuel system:
http://i54.photobucket.com/albums/g9...FuelSystem.jpg

A photo of the "T".
http://i54.photobucket.com/albums/g9.../TheT95Ret.jpg
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WOW!
Great info and pictures are worth a thousand 's
You seem very knowledgeable . My fuel sensor in the front tank was intermittent when i first bought it 2 months ago. i thought i'd solve the problem by working on the grounds but that hasn't gotten it. In fact it's not operating at all now. Is there anything short of removing the front tank i should be going after to see why it doesn't work? (reads low btw)

 

No that is about it, will have to remove the tank and screw on a new sender to the stand tubes.
By the way in case you did not know the grounds for the fuel gauge senders is on the Radiator support passenger side (G100) and in parallel with the one on the drivers side (G101).

The sender:
http://i54.photobucket.com/albums/g9...FDMwiringS.jpg

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