Auxiliary 17 gallon fuel tank 'idea'

With a dual neck aren't you going to run into EVAP issues? There is a timer that activates hours after shutting off the truck that pulls a vacuum on the fuel tank, if you have both tanks connected I'm thinking that the additional air space is going to cause that EVAP test to to time out.

 

I like that dual neck setup! That is a great solution!

 

I decided to just buy a 35gal replacement tank lol.
have one of these coming
https://longrangeautomotive.com.au/Toyota-Tacoma-129L-Replacement~341

 

Now that is done right. How ever could it be more exposed to damage from off road use?

 

sure, nothing a skid plate cant fix, but will see, as i have yet to hit my fuel tank with the truck as its not a rock crawler lol

 

I didn't think there would be EVAP issues. With the auxiliary tank plumbed into the factory venting, the two filler necks connected, fill line (likely with a pump with a check valve) should make the computer see it as one large tank (or so I think). The only issue I could see would be if the computer/ sensor doesn't like the volume of air being drawn to pull a vacuum- if thats the case wouldn't the Long Range 35 gallon tank cause EVAP issues?
The factory filler neck in the link is from an older FJ and it is not sealed between tanks- just a flapper to divert the fuel into one tank or the other- no sealing ability.

Would be happy to hear more info on the possibility of EVAP issues?

Would be nice to know what it costs to your door. Also if you could take a bunch of pics before, during and after install?

Get some bristle board and make a template! Then off to a fab shop...

 

i will take lots of pictures, but i will saw the 3 or so fab shops i asked around for most didnt want to do it and some were 1500+ this is coming in under that from a well known fuel take builder.

 

The volume of air is what I am suspecting. I have to go back into the tech manual which I don't have right now, but I remember reading that the initial purge is a set time period (like 15 seconds), after the pump stops, the reading has to be within a minimum vacuum parameters. The dual neck setup could very well work, this is all very new to me also. Finding the proper information on this is become cumbersome!

The large 31 gallon tank that I previously posted I have gone away with. After pulling the bed off and taking measurements, I am not going to have the proper departure angles, this came to light after realizing I wasn't taking a high clearance bumper into consideration. Plus the baffle and weight issue.

The new tank that I will be building the setup with is going to be from a 94 S-10 blazer (19gal), stock pump and sender that was built for the tank, and using a 6 port fuel switching valve for proper fuel return. The tank, sending unit and pump new from Dorman are very inexpensive, and the fact that is meets automotive standards is another bonus in my opinion.

I am in the middle of my Bussman RTMR project so I should have my entire wiring harness complete for 12 rocker switches and relays, as I get ready to pull wires throughout the truck, I will be running wires from the tank directly to a three position switch to select tanks and using the dash fuel gauge for both tanks. The only issue at this point that I am trying to verify is during a fuel switching event, will the ECU detect the voltage changes between the two fuel pumps handing off power to one another.

I am not planning on touching the EVAP system, the aux fuel tank will only be connected to the fuel switching valve, dashboard fuel gauge, and fuel pump getting wired....and possibly some other special fuel connectors to ensure proper flow.

Ill be watching your thread, and will try to keep mine updated with documentation as I get the build going. I am going to have to put the project on hold for a bit, I am deploying soon.

 

Below is what I was referring to. I'm not sure if you have the 05+ tech manual, if not you can get it from http://www.customtacos.com/tech.old/files/05FSM/repair.html

When you get to the index page from the above link, you can find most of your information in the SFI System: EVAP System section.
The second picture is from a 5 step manual system check procedure. I am assuming when your soak timer and purge event happens, these numbers are part of the .02 inch leak criterion. This is why I am trying not to touch any part of the EVAP system, I can't seem to find any additional info to know exactly what is going on.

 

Cool idea

 

got another picture of the aus 35gal fuel tank. They are super nice to work with too. i am having an extra few fittings installed so i can either do a transfer fill or a gravity feed later on.

 

I want one of these tanks; Please post photos of install when you get to it, would be nice to see how it all goes together. I'd imagine this would increase the Taco lean a bit more but nothing a custom leaf pack or some air bags couldn't fix.

 

mjohn617... That stuff is beyond my technical knowledge!

Hollyhandgranade has his auxiliary tank set up done and is running it without any evap codes;

https://www.tacomaworld.com/threads/piecing-together-an-aux-fuel-tank-setup.475581/

 

Yeah, that is a good point. I have been thinking about going with the dual neck filler Idea and the switching valve, and having both tanks hooked up to the EVAP system. Aside from all the technical details, it looks like multiple people have done it like this and have had no issues. Below is the diagram from Pollak, I am going this route.

 

Ran across a video that shows this type of aux feul set up (first 10 minutes);

https://www.youtube.com/watch?v=vgIZos99HN8

 

I really like this idea. Just might have to install in my 2008 Tacoma. By the way. I do have one of those Downey aux tanks in my 1985 4x pickup. And no, it's not for sale at any price. LOL

 

If you do end up installing one- you can post up a how to on here with pics as you go! Would be great to see this 'idea' come to life!

Yeah the Downey tank was great. I could fill it- drive 2 hours to college- drive around for two weeks and then drive 2 hours home before I needed fuel.

Also had an idea to hinge the new spare tire cradle at the rear behind the aux tank and use it to lift the rear wheels of the truck off the ground either by slowly rolling forward or by using a ratchet strap from the front of the cradle to the rear bumper. Have it so you could pin the rear hinge so it can't fall on you.