How to delete S13 charcoal cannister / Evap system - Page 2 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Presto · 01-31-2020, 01:20 AM

Got a 240sx it’s my first car I’m working on I’m replacing the gas tank which was rusted out again after I tried cleaning the rust the first time, and I just ordered new pump,sending unit, and tank, Previous owner deleted charcoal canister, I’m trying to avoid future rusting of my new parts

These are my options:

1.If I have fuel tank evap nipple>check valve>hard line that runs up To engine bay and cut where I think the charcoal canister might have been (previous owner deleted) + s14 gas cap, am I good on the explosion/implosion/rusting?

2.What if I removed the check valve, capped the line from the evap nipple and buy an s14 gas cap? Am I risking rust and issues still?

3.Can I run a hose from the evap nipple to a filter like in this thread, and buy an s14 gas cap? Or would this let moisture and things into the tank?

I’m just confused but please help me if no one replies I’ll probably just go with option 1 or 2 and hope I don’t blow up or waste $1000

Dsmguy1993 · 02-07-2020, 10:19 PM

I had to do this on my old s13 because I live in the midwest so the old fuel lines got rusted out, sourced the hardlines off another s13 and make shifted my own underbody mounts. What I do with that line is let it vent to atmosphere, but I did not think about using a filter to keep debris out very good idea. Good write up always knew venting was critical, but never knew how much of a safety problem it is too.

ph1tnessjunk1e · 02-13-2020, 04:35 AM

Quote:

Originally Posted by KiLLeR2001

As I expected I knew some information would be flawed.

The fuel check valve works as an equalizer for the fuel tank. On hot summer days, there will actually be positive pressure that will accumulate inside the tank. If you only install a one-way valve (vacuum) or keep the fuel check valve but block off the fuel vent, you will have problems. And by problems I mean premature fuel pump failure.

The fuel check valve will release a little bit of fuel vapor when the pressure exceeds X amount of psi. The fuel cap is vacuum only for S13's. If you vent to atmosphere with no fuel check valve installed, then you basically have an open system and moisture will creep into the tank and then you can say hello to a rusty S13 fuel tank for me.

If you want to block off the fuel vent, you can, but you must install an OEM S14 fuel cap because that acts as a two-way valve just like the fuel check valve.

Personally, I have an S14 fuel cap and a functioning fuel check valve so that way if one fails, the other is there as a fail-safe. I left the factory hard lines alone so it vents out right where the charcoal canister was. Been running it like this for 6 years and no IMPLOSION/EXPLOSION has occurred (like you are implying).

Ok, I want to make sure I do this right so I want to confirm my understanding.

Venting to the atmosphere, even with a filter like the original post says, is not good. In order to properly do this, we must use a S14 fuel cap and fuel check valve that releases pressure at a certain PSI - both are needed if redundancy is desired.

Is that right? If yes, what fuel check valve did you use? Do you know the PSI at which the factory valve releases pressure?

Bleakley · 05-22-2020, 11:46 AM

Speaking for S13’s:
I set up SOHC’s and DOHC’s the same way when you’re stock or N/A and retaining EVAP or just trying to capture fuel vapors (some places are UBER F***ing anal about looking for this).

-I run the 1/4” line from manifold to canister. (Vacuum source between throttle body and engine)
-I run 5/32” line (w/ the factory restrictor installed in the line!) from any source between throttle body and MAFS. Preferably the throttle body nipple. This ensures purge during partial throttle / cruise situations as intended.
—> Retain OEM check valve.

I have ran multiple cars like this for 8-9 years.

Once you go turbo it’s up to you what you want to do as shuttle changes must take place.
What I do for simplicity is delete canister, EVAP, and all the bullshit. I utilize the existing hardline under the car, hook it up to tank vent, then at the other end I put a hose on it and either a) run it to turbo intake or b) put a filter on the end of hose and lay it REALLY close to air filter for turbo intake. Both methods work.
The potential for fuel vapors to gather under hood are slim, but DO exist. I’ve ran it this way for a year or two.
The other simpler option is running the filter to rear bumper or some location out from under car but preferably higher than fuel tank.

01-31-2020, 01:20 AM	#31
Presto Leaky Injector Join Date: Mar 2019 Location: USA Posts: 96 Trader Rating: (0) Feedback Score: 0 reviews	Got a 240sx it’s my first car I’m working on I’m replacing the gas tank which was rusted out again after I tried cleaning the rust the first time, and I just ordered new pump,sending unit, and tank, Previous owner deleted charcoal canister, I’m trying to avoid future rusting of my new parts These are my options: 1.If I have fuel tank evap nipple>check valve>hard line that runs up To engine bay and cut where I think the charcoal canister might have been (previous owner deleted) + s14 gas cap, am I good on the explosion/implosion/rusting? 2.What if I removed the check valve, capped the line from the evap nipple and buy an s14 gas cap? Am I risking rust and issues still? 3.Can I run a hose from the evap nipple to a filter like in this thread, and buy an s14 gas cap? Or would this let moisture and things into the tank? I’m just confused but please help me if no one replies I’ll probably just go with option 1 or 2 and hope I don’t blow up or waste $1000 Last edited by Presto; 01-31-2020 at 02:10 AM..

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02-07-2020, 10:19 PM	#32
Dsmguy1993 Leaky Injector Join Date: Aug 2019 Location: Illinois Age: 27 Posts: 135 Trader Rating: (0) Feedback Score: 0 reviews	I had to do this on my old s13 because I live in the midwest so the old fuel lines got rusted out, sourced the hardlines off another s13 and make shifted my own underbody mounts. What I do with that line is let it vent to atmosphere, but I did not think about using a filter to keep debris out very good idea. Good write up always knew venting was critical, but never knew how much of a safety problem it is too.

05-22-2020, 11:46 AM	#34
Bleakley Zilvia Addict Join Date: Apr 2011 Location: Near Pittsburgh, PA Posts: 634 Trader Rating: (1) Feedback Score: 1 reviews	Speaking for S13’s: I set up SOHC’s and DOHC’s the same way when you’re stock or N/A and retaining EVAP or just trying to capture fuel vapors (some places are UBER F***ing anal about looking for this). -I run the 1/4” line from manifold to canister. (Vacuum source between throttle body and engine) -I run 5/32” line (w/ the factory restrictor installed in the line!) from any source between throttle body and MAFS. Preferably the throttle body nipple. This ensures purge during partial throttle / cruise situations as intended. —> Retain OEM check valve. I have ran multiple cars like this for 8-9 years. Once you go turbo it’s up to you what you want to do as shuttle changes must take place. What I do for simplicity is delete canister, EVAP, and all the bullshit. I utilize the existing hardline under the car, hook it up to tank vent, then at the other end I put a hose on it and either a) run it to turbo intake or b) put a filter on the end of hose and lay it REALLY close to air filter for turbo intake. Both methods work. The potential for fuel vapors to gather under hood are slim, but DO exist. I’ve ran it this way for a year or two. The other simpler option is running the filter to rear bumper or some location out from under car but preferably higher than fuel tank.