Ford F150 Gas Tank Swap into 2000 4Runner

Goal:
I plan to do an in depth review of how I installed an auxiliary tank from a Ford F150 into my 2000 4Runner. Feel free to skip any sections you aren't interested in. With all the partial information out there, my goal is for this to be the one stop thread for information on this tank swap.

Background:
I decided I wanted a 4Runner and purchased a 2002 model. After having it for about 6 months, I decided that I should have done more research before making a purchase. I didn't like the push button 4wd with the disconnecting center differential, I didn't like that it was Cali emissions, etc. So I did more research, then I began the search for a '96-'00 non-Limited model. I found one and bought it, but on the way home my girlfriend (who the car is really being purchased for) noticed something was off. She thought the gas gauge was dropping much faster than it should be. I applauded her awareness and recognition of the problem and told her I would check it when we stopped for gas. Sure enough, we were getting the same gas mileage as in the '02, but ran the tank down much faster. When we filled it from probably about 1/4 tank, it only took about 10 gallons of gas. Knowing that all the 3rd gen 4Runners have 18.5gal tanks, this struck me as odd. So I began research again, which ultimately lead to this modification.


Technical Service Bulletin:
Without going into too much detail, the '99-'00 4Runner had issues where the gas gauge would read inaccurately. The following Technical Service Bulletins (TSB) outline the problem in detail. My '00 4Runner falls into the VIN range where replacing the Fuel Sender and Suction Tube Assembly is recommended.

TSB EL010-00 Fuel Gauge Inaccuracy

TSB EL010-99 Fuel Gauge Horizontal Calibration Procedure


Benefits of the Ford Gas Tank:
I am not new to the Ford tank swap theory. I've looked into it previously as a consideration for my Tacoma. I don't like the location of the stock tank. It is offset to the driver side and fuel is heavy. I don't know if this affects 4Runners as much, but in Tacomas it contributes to the "Taco Lean" which is when the truck leans to the driver side. It also hangs a couple inches below the frame with only a thin skid plate for protection. In my Tacoma I was able to cut out and re-weld a crossmember to lift the tank so it's even with the frame rails. In 4Runners this isn't as easy because of the tube crossmember at the back of the tank. So in my opinion, there are four main benefits.
1. Mid-section ground clearance.
2. Weight distribution.
3. No longer have the potential issue of the driveshaft rubbing the gas tank during articulation.
4. Gives you the option to run whatever rear 4-link design you want.


Additional references and where I gathered much of my information:
There are others, but this is where I spent the most time.
Pirate
TTORA


Important Note:
1. My 4Runner is not Cali emissions and it does not have a charcoal canister or any of the additional emissions gear.
2. I have a 1.5" body lift on this 4Runner.


The Tank:
I chose to buy a brand new tank from an auto parts store. I knew I would be welding on it and I didn't want to have to worry about the cleanliness of the metal or residual gasoline fumes. The tank is an auxiliary tank (rear mount) from a '90-'97Ford F150. I ordered mine from PartsGeek.com and it cost $110.63 after shipping. The part number I ordered was TNKF1G. Here is a link to the tank. There were 18 and 19 gallon options on PartsGeek.com. Stock size in the 4Runner is 18.5gal. I chose to go with a 19gal tank.


Common Options:
There are a few common options when installing a Ford tank into a 4Runner.
1. Install the Ford tank with the Ford pump and sending unit and wire it to the Toyota wiring. If you do this, the gas gauge will read backwards (Empty to Full). People have bent the float arm to correct this and have the gauge read correctly. See the Pirate link above for more information.
2. Install the Ford Tank with the Ford pump and modify the Toyota sending unit onto the Ford pump. This allows the gas gauge to read correctly; however you still have to modify some wiring and I believe you need to add a wire for the low fuel light. See the Pirate link above for more info.
3. Install the ford tank with a Chevy pump and sending unit. Apparently a certain Chevy fuel pump will mount directly into the Ford tank and read correctly on the 4Runner gauge. You would still need to modify it to the Toyota wiring. See the Pirate link above for limited info on this option.
4. Install the Ford tank with the 4Runner fuel pump and sending unit. This requires significant modification to the tank in order to mount the Toyota components. It also requires modification to the Toyota Components in order to make them fit in the Ford tank. This is the method I chose.


My Build:
See the posts 11-23

Nice, this was going to be my plan when I go SAS, will be nice to have this write up! Cant wait to read up.

Also with this setup does it eliminate the driveshaft flexing into the tank? I believe thats why some have done it also in the past.

This is actually one of the first mods I've done to my 4Runner so I haven't had any problems with the driveshaft hitting the tank, but I'm familiar with the issue. To answer your question, it will absolutely prevent the driveshaft from flexing into the tank. The tank is now located completely behind the rear axle and nowhere near the driveshaft. Gives you plenty of room for a more serious 4-link in the rear as well.

midcoma said:

This is actually one of the first mods I've done to my 4Runner so I haven't had any problems with the driveshaft hitting the tank, but I'm familiar with the issue. To answer your question, it will absolutely prevent the driveshaft from flexing into the tank. The tank is now located completely behind the rear axle and nowhere near the driveshaft. Gives you plenty of room for a more serious 4-link in the rear as well.

Click to expand...

Wow, I kind of should have known that. Yes if behind the rear axle how would it rub. LOL. I cant wait to see the install photos.

Sweet. Been thinking about doing this to my '85 as an aux tank, looking forward to seeing your pump and sender mods.

About time dude. Should've done this write up a long time ago. Like when you finished the tank.

It holds 20 gal, right?

I just finished it at the beginning of March. I needed test time to make sure it didn't fail and that the gauge read properly, etc.

Following

Subd

A Word of Caution

*****A Word of Caution*****
Be careful with the mounting screws for these flanges. Then do not require a lot of torque, I found out the hard way. During mock up and pressure testing I sheared a screw. I had to buy a $60 Heli-Coil kit to repair a screw that was worth a few cents. The screws for the cut off valve flange are m4x.7 and the screws for the filler and fuel pump flange are m5x.8. IIRC, they're 10mm long. After this issue, I bought taps and chased all the holes to make sure installation went smooth.

Tank Modification

Tank Modification:
I modified the Ford tank by mounting all the Toyota components to it. This probably isn't the easiest way to do as it requires cutting/welding on the tank, but I decided that I wanted to reuse all the original 4Runner components and keep the wiring simple. The entire swap took about 2 months, working on it when I had time. We have other vehicles so I wasn't in a rush to complete it in a weekend. I definitely recommend taking your time.

Start by removing the tank from the 4Runner. This is much easier if the tank is empty. Methods for emptying the tank include driving, syphoning, removing the fuel hose from the hard lines and routing it to a container then turning the vehicle to ON and letting the pump do the work, etc. I still had some fuel left in my tank and it made life a bit harder.

Once the tank is removed, empty any gas that is still in the tank. I poured the gas out of the filler. The metal filler tube on the tank has a valve on it to prevent gas from spilling out. Unbolt the metal tube from the tank and you will be able to pour the gas out.

Remove all the bolted on parts from the tank. On my tank that included the fuel pump/sending unit assembly, the cut off valve assembly and the metal filler tube.

Purge the tank of any remaining gasoline fumes. I reinstalled the metal filler tube to prevent water from escaping, and inserted a garden hose into the hole from the cut off valve assembly. I let the hose run for about 30-60min, allowing the tank to overflow, to remove any left over gas and fumes. Then I mounted a propane torch to a 10' pole, placed the gas tank on the back side of a large tree, light the torch and held it above the holes in the top of the tank while I hid behind the tree to ensure no fumes combusted. After no explosions with the flame above the holes, I put the flame through the holes to the inside of the tank to make sure no fumes were lingering. Luckily I had no explosions. Perform this step at your own risk with whatever method you choose. I recommend being overly careful.

Now that the tank is purged, the factory mounting rings need to be removed so they can be mounted to the Ford tank. I used a 4.5" cut off wheel and it made quick work of the process. I also cut the Toyota baffle/sump bucket out of the tank and used it in the Ford tank.

The tank that I purchased has 0 baffles.

I didn't take many pictures of the stock tank with the parts cut off, but I did take this one of the sump bucket in the tank so I knew how to orient it in the new tank. The hole in the bucket goes to the front with the channel wrapping around to the back.



So now all the Toyota parts have to be placed on the Ford tank. To start, the Ford tank is 22ga galvanized sheet metal. I am absolutely not a professional welder, and mig welding sheet metal sucks. I looked into a couple tricks, and from what I found you want to use the thinnest gauge wire your machine can handle, make sure the material is clean as always, prevent having any gaps between the material, and be careful with the heat.



I took some measurements, and bought a 12"x18" sheet of 22ga sheet metal from Home Depot to use for mounting the Toyota pump to the Ford Tank. I decided to place it where the Ford tank is supposed to be. I measured very carefully (remember you don't want any gaps between the sheet metal) and cut on these lines.



There will be pictures later where you can see the hole.

Here is the stock filler location on the Ford Tank.



As you can see below, it is a straight tube with no valve. I decided to replace it with the Toyota tube because it will prevent fuel from pouring out in a tippy section or a roll.



I used a propane torch to heat the solder holding the tube in and used a pair of pliers to remove the tube as the solder melted.



Then I began mounting the Toyota flanges. BTW, the Toyota parts seem to only mount to the flanges one way. Make sure you orient the flanges in the proper way on the tank. For example, I wanted the hinge of the filler tube valve to be at the top so I hade to make sure the bolt hole pattern was aligned for that. Always remove galvanization prior to welding.







Then I mounted the cut off valve flange.















Now, skip to "Fuel Sender Modification"

Tank Modification

Now that the fuel sender is modified, it needs to be mounted in the tank. If you follow the TSB, it appeared to me that the float for the new sender would be inside the sump bucket. The old style float was outside the sump bucket, which made more sense to me. The sump bucket should always remain as full as possible to prevent fuel starvation and you want the sender to give you an accurate reading of the amount of fuel in the tank, so I made a bracket for it to mount outside of the bucket. Here are pictures of that bracket process.

Basic shape.



Holes drilled to weld the bracket to the tank.



Some bending.





Some welding.





I determined earlier during the sending unit modification that in order for the float to swing it's full range of motion inside the tank, the center of the mounting bolt had to be 3 19/32" from the inside bottom of the tank. Your measurements may vary, but that's how I determined where to put the hole in the bracket.





There is going to be very little room to work with during final assembly, so I wanted to make sure I could get the fuel sender aligned and supported and only need to use one hand to install the bolt. I made this little tab on the mount so that the sending unit would be supported while I installed the mounting bolt.







Then I chose this location for mounting the bracket to the tank. My decision was based on having enough room to reach my hand inside through where I believed the fuel pump hole would be and have room to get the sender installed and the bolt in.















Then it was time to mount the sump bucket. I drilled out the original pinch welds that held the bucket to the bottom of the Toyota tank so that there was only 1 thin layer of sheet metal attached to the bottom of the bucket. I played around with the bucket's location in the tank, and then marked lines that lined up with the top of ridges in the tank. I drilled a few holes along those lines for mounting. First I needed to modify the bucket so that I would be able to install/access the fuel sender. I did that by aligning the bucket in the tank and determining where my hand would need to go to install the sender. I made some marks on the bucket and started cutting.

I drilled holes here to have a radius in the corners.

Tank Modification

Determined my cut lines.



And went at it with a Dremel. The Dremel cut it very easily.



Here is the final mounting location of the bucket. Remember to remove galvanization prior to welding.









And the access to mount the sender.



Now, skip to "Fuel Pump Modification"

Tank Modification

Now that the fuel pump is modified, you can determine where the mounting hole needs to be in the tank. I held the pump in place in the sump bucket and took some measurements to determine where the flange had to be mounted. I marked those likes on the sheet metal, aligned the flange, and traced the inner diameter onto the sheet. Then I cut it with the plasma.



Once the hole was cut I welded the flange to the sheet metal from the top and bottom.







To mount the new sheet metal to the tank, I used a trick I should have used when bobbing the bed on my Tacoma. You drill holes along the border, close to the edge, and tack weld backing strips. You then tack weld the new sheet to the backing strips the same way. It helps hold everything in place while you weld and helps make burn through more forgiving.









Then I started the same process with the sheet metal. I left the sheet metal long, because I wanted to make sure I didn't have a gap at the far side after bending around the corner.



Once it was bent and tacked, I made a cut line and drilled holes for tacking to the backing strip.



Then I finished the mounting.



Then I welded the seam.

After it was welded I got everything set up to pressure test. DO NOT SKIP THIS STEP! The last thing you want it to have this tank installed and notice you have a leak. Take the time to test your weld and make sure it holds pressure. Even if the tank doesn't leak gas, you don't want it leaking gasoline fumes either. Here is the tank set up for pressure testing. I capped off all the lines and used an old O2 sensor to plug the cut off valve tube. I used a basketball pump with the needle inserted through the rubber cut off valve tube to add pressure. You only want to use 3-5 psi, then spray a solution (I use Windex) around the welds and check for bubbles. Bubbles mean leaks. Mark any locations that bubble and fix the leak.





I had 3-4 very small leaks. I decided to go a little overboard to fix them. I ground down the initial welds and started welding over them again. I covered the holes to prevent metal dust from getting in the tank.





The final welds will be visible in other pictures. Make sure you pressure test after every repair.

I bent and routed the fuel lines to make them fit the new application more cleanly. Here is how they turned out.







The lines were cut to the length I wanted and I chose to install barbed fittings so I could easily and securely attach fuel hose. I ordered the parts from Summit Racing.

I used one of these to adapt both ends of the high pressure fuel line (larger diameter) to a barbed fitting. Both ends meaning the tank side and the vehicle side. They come in a pair. Part

I used these to adapt the smaller lines on the tank to barbed fittings. The lines on the vehicle side already have bulges to prevent the hose from coming off when clamped. Part

I used all the same size barb fittings. Part

Here's a shot of the male fitting being installed and the tube flared. I used a brake line flaring kit that I rented from Advance Auto to install these.



Now, skip to "Tank Mounting"

Now that you've mocked up the tank and have the support system installed, it's time to make it pretty. I primed the tank with self-etching primer and painted it satin black.

Fuel Sender Modification

Fuel Sender Modification
Since my 4Runner required a new sender unit according to the TSB, I purchased the new part and modified it for the tank.

I want to say that the Toyota tank is around 14" tall. The Ford tank is only around 7" at the section I was mounting the sender to. First I thought I would bend the float bar into a shape that would fit, but that wasn't working, so I just made the float bar shorter. Here was that process.

I had a total of height of 6.75" inside the Ford tank for the sender to operate in. This means that the entire swing of the float had to fit inside this height. If the float wasn't maxed out at the top, the tank wouldn't read full. If the float wasn't maxed out at the bottom, the tank wouldn't read empty and I would risk running out of gas with no warning.

I make a bracket to mount the sender so that I could get some measurements. Here is the new style sender without any modifications.

Empty - Lowest point.



Full - Highest Point.



The total swing (delta) of the float was measured from the bottom of the float at the lowest position, to the highest point of the float at the high position. The delta was 9.125". I had to get the delta from 9.125" to 6.75".

I started closest to the sending unit. The section of the float bar that is vertical in the low position was bent upward so that it was now horizontal. I made the bend slightly below where the first bend in the bar was.



I flattened out the rest of the bar so that it was parallel with the ground as well.

I then made a 90° bend that wrapped around the front of the sender unit. There is 1.3125" of bar from the corner of my first bend to the corner of the 90° bend.





I cut the bar after the 90° bend to a length of 1.375". This length of the bar was inserted into the float and the retaining washer was installed behind the float.





After the modification, the total delta from high to low was 6.6875". Pretty much perfect. Here are the new low-high pictures.

Empty



Full



This looks really easy once it's done, but it took a lot of time and guess/check. Hopefully it will be easy to duplicate.

I still had to know where to mount the sending unit in the tank. To do that, I measured from the ground to the bottom of the float and from the ground to the center of the mounting bolt. The difference between these two measurements was 3 19/32". So for the float to sit on the bottom of the tank when empty, the center of the bolt hole had to be that high from the bottom of the tank.

Now, return to "Tank Modification"

Fuel Pump Modification

Fuel Pump Modification
The Toyota fuel pump assembly is much too tall to fit in the Ford tank. I think I have numbers at the house and will update if I find them. It has to be shortened to fit inside the tank. The bracket for the pump is also a recommended replacement part for my 4Runner based on the TSB. I did not replace this part because I was modifying it heavily anyway.

Here is the stock fuel pump assembly.



This is the stock fuel pump assembly without the sending unit.







I will update later with the amount of material that needs to be removed, but here are the cut marks I made of the fuel pump after disassembly. From the top, I removed sections 1 and 3. I kept the triangle section and the bottom section.

*****Update*****
I found my notes. They say that from the bottom of the mounting flange to the bottom of the pump assembly was 11.75" and that it needed to be 7.25". I made a note to remove a total of 4.375"-4.5" of material.



I welded the pieces back together, making sure the angles were correct so that that pump would sit vertically. Pay attention to these angles prior to cutting the bracket apart.

This tube is what shuts off the gas pump. When the fuel level reaches the tube, it creates a vacuum in the tube that trips a valve in the fuel pump and shuts it off. If this tube sits too low in the tank, you will not be able to completely fill the tank. On Jeep TJs, the offered an "oversize tank" but it's really the same size tank with a longer tube. We cut the tube on my sister's TJ and turned her tank from a 15gal tank into an 18gal tank. So to make sure I get a full tank, I modified the tube. I re-drilled the small hole in a location where I made an educated guess that it would be right around level with the top of the inside of the tank. Then I cut the tube the same distance below the hole as it was originally. I believe the tube ended .75" below the hole. I kept the hole in the tube the same diameter as stock as well.





The rest of the tubes needed to be modified as well. When I cut the bracket shorter, I left the fuel return line as long as possible. This is the tube that runs down to the bottom of the bracket. I had to do some bending to get it to align properly with the shorter bracket, but I managed and welded it back onto the tab where it belongs. Then I bent the end by the bottom of the bracket and cut it to resemble the stock configuration. The fuel supply line that connects to the pump had to be re-bent also. Bending these tubes is a guess and check game. I used my hands to bend them and various sockets to bend the tube around to try and get a nice radius with no kinks. Keep bending and checking the fit with the fuel pump on the bracket to make sure there isn't interference. Leave the tubes as long as possible until they are bent properly. The longer the tube is the easier it is to bend. Here is my final bracket.





Here it is with the pump installed.





I did not modify the wiring at all, I just left it long.

Now, return to "Tank Modification"

Tank Mounting

Tank Mounting
Well this was fun. Making the bracket was not difficult. Figuring out what to make and how to make it was a pain in the ass. I'm very happy with what I came up with and it made tank install easy.

*****NOTE*****
I have a 1.5" body lift installed. Measurements or mounting will be different without one.

This is what you're dealing with at the start.







You need to cut out the spare tire crossmember. I decided to use my plasma, and this is what I was left with.







I also removed the tail pipe of the exhaust to allow more room. I still need to re-rout the exhaust after the muffler.

I used a combination of 2" angle and 1.5" flat bar for the mount. I chose to use 3/16" material thickness. I started with the rear of the frame by cutting some 2" angle to fit snugly between the frame. I think I left had 1" from the end of the frame to the inside of the angle, so there was some material extending beyond the frame. I used a couple clamps to hold it in place.

From there I started messing around with tank location by mocking it up and supporting it with jack stands. The tank has a seam around it and I left the rear seam flat and made is sit flush with the bottom of the angle at the back of the frame. I then eye-balled the tank level to the bottom of the body and decided how to mount the front end of the tank. I decided to use angle again, but it had to be suspended below the frame. I used 1/4" plate to extend it down because that's what I had laying around. The bottom of the angle is located 3.75" from the bottom of the frame, measuring vertically up the 1/4" plate. I made this assembly fit tight between the frame rails so that I could position it and test fir the tank without having to hold it in place. When I found the prefect location that supported the tank well, I traced the edges of the bracket with a Sharpie so I knew where to put it later. For now, I left it in place and moved to the next step.

I used 1.5" flat bar to make an upper support system for the tank. I essentially made an "H" that laid in the ridges on the top of the tank. The ends were bent to wrap around the tank. It was a bit of guess work with the bending, but it turned out well. This "H" was then laid on top of the tank and the tank was put back in place under the 4Runner. Once in place, the "H" was tacked to the front and rear support bars.

The whole assembly was then removed from the 4Runner. I did this on purpose because if I welded things in place, it would be almost impossible to get the top side painted. So it was pulled out and I finished welding the "H" to the front and rear bars.

The next step was to figure out how to support the bottom of the tank. For the front bar I decided that I wanted the straps to slide through the bar and bolt on the back side. For the rear bar, I simple drilled a couple holes and welded nuts to the back side. With this design, the front of the tank is supported by the angle during installation. I simply have to support the rear of the tank, slide the straps through the front bar and install a bolt at the rear. Then the tank is supported while I install the front bolt.

When that was all said and done, here was the result.

Mocking it in place.







Final welding.











Fit on tank. You can see that the front seam on the tank was flattened against the tank to allow for proper mounting. As said earlier, the rear seam was left flat because it sits flush with the rear angle. The corners were also rounded to remove the extra material.







Front strap bolt mounts.



Nuts welded to back side of angle for easier assembly/disassembly.



If you notice on the front piece of angle, I drilled a hole and welded a nut on the back side. I did this at every ridge in the tank. These holes/nuts will be used for future mounting of a skid plate. The nuts for the skid plate are 5/16".

The nuts for the straps are 3/8".

Once all the welding was done, everywhere that was not being welded was painted and allowed to cure.

Tank Mounting

Once the paint was dry, the assembly was placed back under the 4runner. The rear bar was clamped in the proper location and the front bar was placed inside the previously made marks on the frame. The tank was test fit, then the assembly was welded in place and painted.



















The bottom straps will be shown later.

Wiring

Wiring
The wiring wasn't bad. The factory connector had the be extended to reach the new pump location. The connections can easily be accessed under the driver side rear seat. Flip up the carpet and unbolt the cover.

There are 3, 22ga wires and 2, 18ga wires on the stock connector.

I used a length of paracord to neatly wrap 3, 22ga wires. This was a bit of a pain because it was a tight fit. The inner cords were removed and replaced with the wires. Once it was done, it turned out well.

Make sure you keep your colors straight.

First I soldered the 22ga wires to the cars wiring harness. Each wire was soldered and covered with heat shrink.



Then the whole bundle was covered with heat shrink that went over the paracord sleeve.



The 18ga wires were soldered and covered with heat shrink as well.



I bought some electrical expansion wrap from McMasterCarr and covered the whole wire bundle with that to keep it neat. It was also covered with heat shrink at the end.

The connector was done the same way.





Here is the final routing of the wire. I made it long for easy assembly.



That's pretty much all there is to it.