okay so I am not doing it in a third gen but this is the best place I could think to ask I am doing it in a chevy truck dual tanks and I want to run a external pump, I figured I would just y the return line in after the tanks are y, but would the returning fuel pressurize that tank going the wrong way? any advice would be appreciated.

 

Without controlling the return line, one of the two tanks is likely going to receive more of the return flow and thus will always be full. Without a full fuel transfer system as in aviation applications, there is no easy way to completely isolate one tank.

 

Nuggie, when you say dual tanks, do you mean in truck tank plus one external? Or, two external? If two external, do you have a low fuel leveling line? I have had a couple of trucks that I have added external tanks to, and had great success. (2008 GMC & 2012 Dodge 3500 dually) if you Y the tanks, you can add a two way valve/switch controlled in the Y for feed fuel. A one way valve for fuel return that you can plumb into your feed line you will also need to vent both tanks and It will be necessary to use a regulator/gauge. You can get very creative on fuel gauges, etc. NAPA sells all the parts - use an old ford van for reference and schematics. Hope this helps, this is a do-able project. Northern tools sells external tank pumps that I have had good success with. Best of luck, byron

 

87+ Gmc used a solenoid valve for the return on dual tank TBI. Google should result the diagram, and the parts should be available.

-- Joe

 

the truck already has to tanks I am kinda confused on where you went with that Buickstaged. it already has the tank selection switch and I planned on feeding in the return line into the feed line right before the pump (probably up in the engine compartment) I figured with the pump drawing from that line it would build to much pressure plus if I need to I could use 2 check valves one to make sure it doesn't try to pull from an empty return line and another so it doesn't pressure back into the tank.

 

No.. No..

You need to tie the return solenoid off the tank switch, so that the return goes to the proper tank.

Just buy the right part, and plumb it properly.

-- Joe

 

how would I do that the sending units don't have a pot for a return line other wise I could just get another valve solenoid and just control the returns hat way. is it poassible to get different sending units for those tanks?

 

Yes. 87+ is EFI. Just get the correct sending units, in tank pumps, etc.

-- Joe

 

Nuggie, are both tanks set at the same horizontal plane? If yes, you need a cross feed at the lowest point of the tank. If not, and one tank is higher than the other, you can purchase a one way valve that is a gravity feed. It will not overflow out the original and lower tank. Look at this feed from a company called RDS. If you leave the valve open, and you plumb the feed line to the highest tank, it will feed via gravity to the lower tank. If your gauge is stock, it will show as full until the highest tank feeds into the lower tank. When the upper tank is empty, and fuel is used out of the lower tank your gauge will indicate the level of fuel as you use the lower tank of fuel. The other option is to plumb the return line to the lowest level tank. That is how my factory setup is and has not been an issue. This is on a 2012 ram diesel, I also did a 2008 gmc diesel. In any event, be sure to have both tanks vented so the fuel pump does not either suck the walls in on the tanks, or has to work so hard that it overheats. Hope I didn't confuse you. Byron

http://www.northerntool.com/shop/too...5139_200625139

 

I love the 87+ sending unit idea will those fit in the tank with out modifying the tank? because then I could just use an f body fuel pump in each tank and just use the switch to control what tank its coming out of, would I need high pressure line for the return or could I just use a long section of metal brake line and rubber hose to connect them? how would I wire it to know what sending unit is giving me the fuel level or should I just get another gauge so I can see both fuel level indapenditly?