I was wondering how and what it would take to use an auxiliary tank that's mounted in the bed and have it tapped into your fuel system? Having it switchable like two tanks on the OBS would be cool and nice but is not necessary.

Would it need it's own pump? And where I run the lines to? And adapt them in? Any info?

If worst comes to worst, would I be better off somehow getting my auxiliary tanks fuel to transfer into the stock tank and run it from there?

 

I have this setup with a 110 gallon aux tank in my bed. After plenty of thought I opted to go with the aux tank diesel kit sold on ebay. It makes sense for a few reasons. The first and biggest concern was not to dink with the stock configuration in terms of return lines, electrical etc.


Mine will autofill the stock tank without worry of overfilling and can be shut off at a simple gate valve. This allows you to isolate the aux tank. Use your current fuel gauge and takes about an hour to painlessly install.


The other consideration was safety. I did not bolt my tank down. In the event of a rollover the tank will eject.


I run WVO and this setup allows me to run reg diesel (in the stock tank) when temps are very low and WVO after warmup and for cross country travel/trips. Seems to work well.


The other positive aspect is that your stock tank will allow the fuel blend to be properly filtered by the pickup screens on the pickup and you don't have to add a prefilter to it. It's a simple cost effective remedy and can be returned to stock just as quick if you decide to sell out.


Denny

 

If you could get by with 44 gallons and no place to put your spare tire you could just get an EX tank and throw in the truck.

 

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Most folks either use the aux tank as a main fill tank and let it gravity feed into the OEM tank and when the fuel gauge drops, fill up the aux and the OEM tank at the same time and go from there. The other option is to manually fill the OEM tank from the aux tank as needed either through opening and then closing the valve or running a separate fuel pump to pump the fuel from the aux tank into the inlet tube for the OEM tank.


One issue you need to consider may be your state and local laws that apply to gravity fed aux fuel tanks. Some states are a little picky when it comes to adding aux fuel tanks. I have a 91 gallon aux tank and I transfer the fuel with a Holley fuel pump and a switch on the dash and I really only use it for emergencies. I originally purchased it after I spent 20+ hour sitting on I-80 waiting for the plows to finally get the road open. Now the main use is to have extra fuel on hand in SOCAL in case we have an earthquake that is large enough to shut down local services. I always carry about 50 gallons in the aux tank and cycle it out every 3 to 4 months or so. If the computers go down and the pumps don't work I know I will always have at least one full tank of fuel (OEM) on hand just in case. Now the downside may be the space you have in the bed of the truck. I have a fuel tank/tool box combo and between that and my 37" spare and other junk I carry around, not much room left over.

 

If your Aux tank dumps into OEM tank, how do you keep the "pump fuel" separate from your wvo?

I'm trying to do similar... Keeping the OEM tank with "pump fuel" and an alternative fuel in the Aux tank. But I don't want them mixing if at all possible...

 

You can't (legally) if you run the aux into the OEM tank. The only way to do that is to set the aux tank to provide fuel directly to the engine. That would take some rather involved mods and I have never seen anyone try it. In CA it would be illegal (although everything is illegal out here) to modify a fuel system so that an aux tank pumps directly into the engine. The only reason my setup with a fuel pump is legal is because I am pumping the fuel into the OEM tank before the OEM pump sends it into the fuel bowl.

 

It's not hard to do. Just add a 6 port valve and a switch. The fuel pump is on the frame under the drivers feet, splice the line further back. If you get the correct sender unit you can even use the factory fuel gauge to read from the aux tank but it takes a few minutes to catch up after you flip the switch.

For WVO, check out greasecar. They have a intelligent system to switch tanks and purge the lines automatically. They also have some good rebuildable valves.

 

If you simply splice the line what do you do with the fuel that is returned to the OEM tank? You might pump WVO from the aux tank but the return line is mixing it back into the regular fuel (OEM tank) for the OP's proposed setup.

 

That's where a system like greasecar comes into play. Rather than using a 6 port valve that switches the feed and return lines simultaneously there are separate valves. So when you are running off WVO and ready to shut down, you switch the feed to diesel to purge the system. You end up with a small amount of diesel in the WVO but that's not as big of an issue as the WVO sitting in the system when it's cold. There are also provisions for starting on diesel and switching to WVO after it warms up. Alternatively you could just get the separate valves and flip the switches yourself one at a time to give the system time to purge.