Fuel Tank Relocation (and new Rear Bumper design)

[MN4runnerman]

Not sure if I missed reading it or if people haven’t posted about it so I’ll ask. For the people who have done this how did you plumb the filler neck vent line? Or did you guys buy a universal internally vented filler neck? I was gonna modify the OE one and weld a bung on the tank and just thread a barb fitting in. I’ve already welded on the Toyota flanges on the tank and everything.

 

[Kirk D]

Not sure if I missed reading it or if people haven’t posted about it so I’ll ask. For the people who have done this how did you plumb the filler neck vent line? Or did you guys buy a universal internally vented filler neck? I was gonna modify the OE one and weld a bung on the tank and just thread a barb fitting in. I’ve already welded on the Toyota flanges on the tank and everything.

I used a Russell -8 tank bung, drilled an extra hole into the tank, and tightened it up through the pump opening. I then cut and teed into the factory vent line on the filler neck as high up as was feasible with 1/2" fuel line to prevent liquid phase gas from settling in it and plugging it. Having dealt with a lot of the internal vent setup that ford has used forever I hate it. I find that separate is far more serviceable. I was also able to leave the line long along with my supply, return, and electrical lines so I can drop the tank to the ground with everything except the filler neck still connected for service.

 

[jkeith.w]

Just a heads up if anyone was considering a bumper..

 

[Team_Jake]

For those that have done the tank swap, what did you do with your exhaust tail pipe? I'm trying to figure out how to do mine (keeping in mind, I've gotta keep mine CA smog legal and I don't have a body lift).

 

[Kirk D]

Without the body lift it’s difficult. Only option is to go out before the rear tire between the frame and lower link. I’ve done it in the past. Depending on your muffler it can significantly increase the sound in the cab though.

 

[MN4runnerman]

I just cut the flange off the back of the muffler and clamped a turn down pipe to it. I don’t have a body lift so that was the only thing I could think of doing. Not much help sorry

 

[Team_Jake]

I just cut the flange off the back of the muffler and clamped a turn down pipe to it. I don’t have a body lift so that was the only thing I could think of doing. Not much help sorry

Like this?

This might be my only reasonable option. Is your exhaust any louder? Is excess heat/fumes under the rear passenger seat a concern?

...

Edit: Photo should show now

 

[MN4runnerman]

Like this?

This might be my only reasonable option. Is your exhaust any louder? Is excess heat/fumes under the rear passenger seat a concern?

Sorry the picture doesn’t work so I can’t see. The flange coming off the muffler that connects to the tailpipe I cut. I cut it so that it was perfectly horizontal. Slid a turndown pipe over it and clamped it. I have not had the chance to hear it I’m still working on some engine stuff. My 98 beater truck has the same setup though. I did not notice any sound difference at all. On my 99 that I’m working on right now the catalytic was stolen off of it and instead I put a resonator pipe in. I have no idea what it’s gonna sound like or if it will be good or bad. Can’t wait to find out lol. I’ll get back to you on if there is any heat or fume issues but I do not think there will be unless your idling in one spot for long period of time

 

[MN4runnerman]

Like this?

This might be my only reasonable option. Is your exhaust any louder? Is excess heat/fumes under the rear passenger seat a concern?

...

Edit: Photo should show now

Yep exactly like that!

 

[Kirk D]

I’m of the belief you’ve gotta get it out from under the truck but that’s just from personal experiences. One is that if you roll down the rear window at all it’s all gonna roll back into the cab. And the other is that that heat will be carried back over the rear axle and heat the rear tank. Yes it will be highly dissipated while in motion but over a long pull it will affect things. Like excess vapor loss from the rear tank or loading the canister especially on the hot summer asphalt.

As an example, once had a friend cut off the exhaust on a caged truck with no bed, granted he had no down turn, but it heated the fuel cell enough to literally boil the gas out the vent and all over my windshield while climbing the highway up to big bear.

Just something to keep in mind.

 

[jkeith.w]

For those that have done the tank swap, what did you do with your exhaust tail pipe? I'm trying to figure out how to do mine (keeping in mind, I've gotta keep mine CA smog legal and I don't have a body lift).

The tank is cheated over to the left so that there is more room on the right to snake the exhaust past its front right corner if needed (over the crossmember, like stock). I'd definitely wrap it where it passes by the front corner of the tank though.

Additionally, the inside fender wall there has a very portion of single-layer steel that does not penetrate into the cabin - I'm going over the frame and through that on my install to get the pipe behind the tire. A body lift definitely helps here, but there's no reason to stick with a 2.5" pipe back there, either IMO.

 

[MN4runnerman]

I had some more time to take a look at it this afternoon. For now I’m gonna leave the turndown pipe on the muffler and just see how it goes. If there’s too much of a fume smell I’ll change it. Looking at it though if you cut the flange off like I did and use an adapter to reduce the tail pipe down to a smaller diameter pipe it wouldn’t be too hard to make a custom tailpipe that would snake by the gas tank. Without a body lift I don’t think you’d be able to run it above the frame even after trimming some of the body.

 

[phattyduck]

For those that have done the tank swap, what did you do with your exhaust tail pipe? I'm trying to figure out how to do mine (keeping in mind, I've gotta keep mine CA smog legal and I don't have a body lift).

For smog purposes, you can do anything you want after the cats... So no worries about smog issues. Make sure the outlet is easy to get to if you want your smog tech to be happy with you.

-Charlie

 

[MN4runnerman]

Anybody have issues wiring the ford fuel pump to the Toyota harness. When I turn the key to the On position I don’t hear it running. Cranking it to start I can hear it running. I must have something backwards. I though I had it right when I spliced the wires. Anybody have a diagram on what they did? Thanks guys

 

[Bad Luck]

Anybody have issues wiring the ford fuel pump to the Toyota harness. When I turn the key to the On position I don’t hear it running. Cranking it to start I can hear it running. I must have something backwards. I though I had it right when I spliced the wires. Anybody have a diagram on what they did? Thanks guys

I may be wrong but I don't think toyota sends a prime signal to the fuel pump. I think it only starts pumping when you try to start.

 

[phattyduck]

I may be wrong but I don't think toyota sends a prime signal to the fuel pump. I think it only starts pumping when you try to start.

You are not wrong. There is no pre-priming of the fuel pump on the 3rd gen 4Runner. The pump is only on for key in the Start position or the engine is running. (part of the reason so many have a longer than normal crank time)

-Charlie

 

[turbodudey2]

You are not wrong. There is no pre-priming of the fuel pump on the 3rd gen 4Runner. The pump is only on for key in the Start position or the engine is running. (part of the reason so many have a longer than normal crank time)

Hmm. That's strange. I always thought there was a prime pulse. When I turn the key to run I always wait about 1.5 seconds before starting. I can hear/feel the fuel pump prime during that time.

Is there a difference between model years?

 

[MN4runnerman]

Ok my engine work is done. Gotta say I’m a little apprehensive starting this thing. So from what you guys are saying there is no prime signal with the key in the on position. I’ve only ever replaced mechanical fuel pumps on carbureted motors where you can prime the pump and pretty much have it fire up. For the guys who have done this how long did it take for you to fire up the engine? Fuel lines were blown out with air. New fuel filter. Hard lines that are spliced into the Oem lines going all the back to the pump with hose connections connecting to the pump. I can hear the pump running when I crank. Think the longest I had it crank was 10 seconds. I just don’t want to wreck anything. Please advise!! Thanks guys. Wiring the toyota harness into the ford plug would be helpful!!

 

[phattyduck]

With a return-type fuel system that the 4Runner has, the fuel lines should fill up fairly fast (say 10 seconds max). I just did my fuel filter and it started almost immediately, died once and restarted normally right after.

The diagnostic connector in the engine bay may still have the Fc and B+ connections in it (haven't checked, couldn't find it on the diagrams either...) - if it does, you can put a jumper in there and it should turn on the fuel pump with the key in the ON position for debug purposes. That's an OBD-I Toyota trick... not sure if it works on the newer (ha! 20 year old) Toyota stuff.

-Charlie

 

[kalisoze]

Any update on the swingout?