Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - View Single Post - How to delete S13 charcoal cannister / Evap system

Kingtal0n · 08-07-2019, 01:39 PM

I need to bring this back because its part of 240sx that I have no clue how to deal with.

haaaaalp

My questions are for S14 only

Right now in a swap I have the 3/8" fuel line typical running to the engine bay from the little plastic box in the bumper, like we always used to do for swaps

And its the same as the last 20 years- the tank never seems over pressure, or under pressure, and the fuel demands of the engine are huge. So I know its sucking air from somewhere (that line?)... Into that black box? I'll bet theres no filter in there. And I read above S14 caps are also breathing, there must be a filter inside them at least? In any case. Atmospheric air contains water, and dirt, which should be eliminated or controlled before the air is allowed into the fuel tank, the E85 (drinking alcohol or "ethanol" etoh) will absorb any water and if it can absorb enough it will turn to shit and make a huge mess of everything "E85 disaster". That's why you can't just put a hole in the tank to relief pressure when using E85. It needs to be checked... but the check system can't ever be allowed to fail so make it redundant, use at least two lines with checks in case one fails.
I think I solved it but I have a feeling the cap isn't 100% sealed at rest, and neither is mystery box. So I have a terrible feeling that I will need to disable the fuel cap vent and install an aux vent with a desiccant/drier to achieve a fully stable container of E85 for long term storage, or at the very least a checkvalve to prevent air from exchanging with atmosphere.

how doesn't this issue affect regular flex trucks? Are the fuel caps 'better' checkvalves? Are there warning in the owner's manual about leaving E85 in a fuel tank for long duration? are the tanks so well sealed up that air cannot enter unless it is replacing air, and that's all the air that is allowed. For years that's what I assumed that 3/8" line did, one-way valve for atmospheric air to enter the fuel tank quickly. I am okay with that kind of system but trusting the 20 year old stuff to work that well without testing it, to be 99% air tight to protect alcohol seems like rolling the dice. I don't wana just dump E85 in the tank without first testing it. So I am going to apply a positive pressure the tank manually and see what happens I guess. Only a couple psi max of course. And the same with vacuum if I can manage somehow. I suppose this is the only way to discern behaviors from scratch. Any advice is appreciated and I'll share what I find if I ever get around to doing this.

I might just goto a junkyard and pull apart the tank of a flex fuel truck just to see. Oh yeah that'll be much easier than looking in the service manual...

08-07-2019, 01:39 PM	#28
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,646 Trader Rating: (17)	I need to bring this back because its part of 240sx that I have no clue how to deal with. haaaaalp My questions are for S14 only Right now in a swap I have the 3/8" fuel line typical running to the engine bay from the little plastic box in the bumper, like we always used to do for swaps And its the same as the last 20 years- the tank never seems over pressure, or under pressure, and the fuel demands of the engine are huge. So I know its sucking air from somewhere (that line?)... Into that black box? I'll bet theres no filter in there. And I read above S14 caps are also breathing, there must be a filter inside them at least? In any case. Atmospheric air contains water, and dirt, which should be eliminated or controlled before the air is allowed into the fuel tank, the E85 (drinking alcohol or "ethanol" etoh) will absorb any water and if it can absorb enough it will turn to shit and make a huge mess of everything "E85 disaster". That's why you can't just put a hole in the tank to relief pressure when using E85. It needs to be checked... but the check system can't ever be allowed to fail so make it redundant, use at least two lines with checks in case one fails. I think I solved it but I have a feeling the cap isn't 100% sealed at rest, and neither is mystery box. So I have a terrible feeling that I will need to disable the fuel cap vent and install an aux vent with a desiccant/drier to achieve a fully stable container of E85 for long term storage, or at the very least a checkvalve to prevent air from exchanging with atmosphere. how doesn't this issue affect regular flex trucks? Are the fuel caps 'better' checkvalves? Are there warning in the owner's manual about leaving E85 in a fuel tank for long duration? are the tanks so well sealed up that air cannot enter unless it is replacing air, and that's all the air that is allowed. For years that's what I assumed that 3/8" line did, one-way valve for atmospheric air to enter the fuel tank quickly. I am okay with that kind of system but trusting the 20 year old stuff to work that well without testing it, to be 99% air tight to protect alcohol seems like rolling the dice. I don't wana just dump E85 in the tank without first testing it. So I am going to apply a positive pressure the tank manually and see what happens I guess. Only a couple psi max of course. And the same with vacuum if I can manage somehow. I suppose this is the only way to discern behaviors from scratch. Any advice is appreciated and I'll share what I find if I ever get around to doing this. I might just goto a junkyard and pull apart the tank of a flex fuel truck just to see. Oh yeah that'll be much easier than looking in the service manual... __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240 Last edited by Kingtal0n; 08-07-2019 at 02:31 PM..