S14 Fuel Return Questions

[240msh]

I'm having an issue with my fuel return line, someone cut it and reconnected the two hardlines with a 5/16 fuel line hose. Now this is my question, ive had 3 s14's, never had such a stupid issue in my life, why does it keep leaking?? Ive tried fixing it 7 times. I got a pipe cutter, cut the janky ass hardline, got a flare tool, flared it, slid my fuel hose over it and double clamped it and it STILL leaks. I'm thinking its corroded inside, but what doesn't make sense is fuel cleans that? Ive been driving the car for a few months with 0 issues and out of no where this happens. Let me know what you think before I just buy new lines all the way to the tank. Thanks

:picardfp:

[unicoder]

Are you sure it is 5/16 high pressure fuel hose? I had the same issue and turns out the auto parts guy just eyeballed the hose and gave me the wrong size. Still fit but would leak

[LoSt180]

I've had to really tighten down on hose clamps for my fuel lines to get them to stop leaking.

[Kingtal0n]

Yes factory lines S14 feed/return appear to be 5/16"

I actually used braided -6an hose on mine with hose clamps which seems to fit perfect.
I ran these to some 5/16" hardline which I flared using the rental flare (1-stage flare on the end) so I could continue using hose clamps throughout the system.
https://s19.postimg.cc/gfujd8q2b/image.jpg

This is track legal and it eliminates AN fittings which can be a unique failure point when they are cheap AN fittings (ebay $3 fittings).
Also I am not sure why -6an (3/8") hose fits 5/16" fuel tube. I tried 3/8" Fuel tube and there was no way to get the -6an fuel hose over it. fwiw
also 5/16" is the outlet size of the Aeromotive stealth style pump(s), which support 500-600bhp

[240msh]

Yes factory lines S14 feed/return appear to be 5/16"

I actually used braided -6an hose on mine with hose clamps which seems to fit perfect.
I ran these to some 5/16" hardline which I flared using the rental flare (1-stage flare on the end) so I could continue using hose clamps throughout the system.
https://s19.postimg.cc/gfujd8q2b/image.jpg

This is track legal and it eliminates AN fittings which can be a unique failure point when they are cheap AN fittings (ebay $3 fittings).
Also I am not sure why -6an (3/8") hose fits 5/16" fuel tube. I tried 3/8" Fuel tube and there was no way to get the -6an fuel hose over it. fwiw
also 5/16" is the outlet size of the Aeromotive stealth style pump(s), which support 500-600bhp
Looks super good man, I'm gonna end up doing that honestly. My fuel return hardline ended up having a little pin hole leak about a inch away from were I was clamping it.. I just used a pipe cutter, flared it again and it fixed the issue haha was getting mad for no reason lol

[240msh]

Yes factory lines S14 feed/return appear to be 5/16"

I actually used braided -6an hose on mine with hose clamps which seems to fit perfect.
I ran these to some 5/16" hardline which I flared using the rental flare (1-stage flare on the end) so I could continue using hose clamps throughout the system.
https://s19.postimg.cc/gfujd8q2b/image.jpg

This is track legal and it eliminates AN fittings which can be a unique failure point when they are cheap AN fittings (ebay $3 fittings).
Also I am not sure why -6an (3/8") hose fits 5/16" fuel tube. I tried 3/8" Fuel tube and there was no way to get the -6an fuel hose over it. fwiw
also 5/16" is the outlet size of the Aeromotive stealth style pump(s), which support 500-600bhp
Also, do you just leave your 3rd line open like that for a vent? that's the one that goes to the charcoal canister right? ive seen s14's use a vented gas cap and was wondering about all that. btw how much was your s15 tank top hat?? or is this a s15 :naughty:

[Kingtal0n]

Also, do you just leave your 3rd line open like that for a vent? that's the one that goes to the charcoal canister right? ive seen s14's use a vented gas cap and was wondering about all that. btw how much was your s15 tank top hat?? or is this a s15 :naughty:


Actually that tube uses return fuel to pull in additional fuel over the fuel sump area. I forget what its called but I assumed that it was a vent (like you and many others do) only to find it actually will rain gasoline all over the back of the car if you don't connect it proper.

Its an S15 topper, i used it to relocate my fuel lines to the other side of the car, I put my exhaust downpipe on the OEM side.

[afishysilvia]

I’ve been reading all over for this, can some one clarify. I have left my vent line open and while I don’t see any traces of gas can I leave it open or should I put a plug? I’m getting strong gas fumes in the cabin. Most are saying since it’s s14 we should have a gas cap that’s capable of doing the pressure release.

[Kingtal0n]

where and how did you find and access the vent tubes on the fuel tank? the only way I know to get at them is to remove the tank completely. So you are saying you removed the tank, messed up the fuel vents, then put the tank back in? SO take it back out and fix them?

[afishysilvia]

No I just disconnected the hardline in the engine compartment where it would go to a soft
Rubber line. I was considering removing the vent hard line and coil the hose somewhere in the diff area?

[Kingtal0n]

No I just disconnected the hardline in the engine compartment where it would go to a soft
Rubber line. I was considering removing the vent hard line and coil the hose somewhere in the diff area?

There is some kinda mysterious black box in the rear quarter panel of the 240sx S14. It runs a 'vent line' (is that the line?) to the engine bay, for emissions (charcoal canister or something)

I was about to address this issue on my own car because when we swap the motor we ditch the charcoal/egr/etc and that line is still present (and smells like it has gas in it) plus weight savings. I've never done it before though so I don't know anything about it yet.

My method was going to be: look through the FSM to find this setup and see how it works first. Then come ask on zilvia about it if I had questions. Because I've never removed one before and I know it needs to go but also I will still need some kind of vent/capture for the tank to keep the gasoline from simply evaporating right out of the tank all the time. The tank needs to be nice and sealed up to keep our $$$ inside it if you get what I'm saying. So do us both a favor and check out the FSM and tell me what you find :D

[LoSt180]

There is some kinda mysterious black box in the rear quarter panel of the 240sx S14. It runs a 'vent line' (is that the line?) to the engine bay, for emissions (charcoal canister or something)

I was about to address this issue on my own car because when we swap the motor we ditch the charcoal/egr/etc and that line is still present (and smells like it has gas in it) plus weight savings. I've never done it before though so I don't know anything about it yet.

My method was going to be: look through the FSM to find this setup and see how it works first. Then come ask on zilvia about it if I had questions. Because I've never removed one before and I know it needs to go but also I will still need some kind of vent/capture for the tank to keep the gasoline from simply evaporating right out of the tank all the time. The tank needs to be nice and sealed up to keep our $$$ inside it if you get what I'm saying. So do us both a favor and check out the FSM and tell me what you find :DWhen I did my swap, I used the small charcoal canister in the engine bay from the JDM S14. Then under the quarter panel, I removed the large canister and connected the lines together from the tank to the front of the car.

The JDM canister is vacuum actuated vs the USDM one that has electric solenoids. Verified connections using JDM and US FSMs.

https://uploads.tapatalk-cdn.com/20180923/80f584f5931f537f7d1946da7e0d6a56.jpg

[afishysilvia]

I will try some stuff out, I don’t have any canister nor have plans to install one. My V8 swap doesn’t need it. Just was curious if it should be open or capped since the s14 has a built in relief.

[Kingtal0n]

In the spirit of economy and control of fuel smell I am going to run one.

That Silvia canister was a great idea thanks. I don't know how much difference it will make but in my swap I am doing everything I can to improve mileage and contain fuel vapors. I don't ever want to smell gasoline when the engine is off, if they need somewhere to go. When you open the cap to re-fuel and replace all the vapors with gasoline they escape and that is all lost fuel, more than the evap system captures probably, so it isn't really a mileage concern it seems like. But I can't see how it would hurt (except for weight) so I will compare weight with function (if there is any difference) and make a decision later about what to do permanently.

I just wish I knew what was going on back there in the quarter panel, it looks like so many hoses and wires for something you would think is so simple. Everytime I look in there to do something with it, my hands get filthy immediately and a bunch of sand and dirt falls into my face, and I just sigh, swear I'll come back some other day and do something about it next time. Its been like two years and seven attempts and I still havn't done anything lol

[240msh]

I will try some stuff out, I don’t have any canister nor have plans to install one. My V8 swap doesn’t need it. Just was curious if it should be open or capped since the s14 has a built in relief.

Im glad to see Im not the only one completely confused by that lmao, I seen a post about a vented gas cap and called it a day. Id really like to know what I actually should do about that line, cause I really don't want it lol