84 F150 Dual Tank questions
Just got an 84 F150 and it has dual tanks. The odd thing is that it has the regular tank under the bed however there is another inside the bed with a built in toolbox on top of it. I've never seen it before. Is it aftermarket??
I was also wondering if anyone knew exactly how the dual system works. I have a switch on the bottom of my dash and it's a 3 position switch (left, middle, right). All the way left and it gives me a reading on my fuel gauge and it appears to be accurate (i.e. full after a fill up). When I switch it to the right, the gauge goes to empty. How do I fix that??
AND......I noticed that I accidentally placed the switch in the center position for about a week and my main tank, the only one that gives me a reading, appears to have had fuel used from it. Does the center position move fuel from one tank to another??
I know I have a mechanical pump on my 300 straight 6 engine, I can see it, but are there fuel pumps in the tanks as well? The external tank in the bed has a wire leading from something on top of the tank and I get a variable reading with a volt meter. It jumps from 0-4v or 0-5v about once per second. Anyone know how this system works.
The more descriptive the better!!!
Any help would be great!!!