Pressure build up in gas tank

[John Staton]

So when I go to refill my tank there is a lot of pressure that is released when I loosen the cap. I guess I had gotten kind of used to it, but it really worried my son the other day at the gas station. I have read a few threads on this and I see the charcoal canister being referred to, but mine has been totally desmogged so I dont have any of that. Additionally, I had the tank replaced at the dealer. I am wondering if it simply getting the correct gas cap would fix it. Is the cap supposed to relieve pressure?? I do remember replacing the one that came with the truck because I wanted one with the little slit where you could hook it on the door while you filled it up. I have had the truck about 18 months and cannot remember if I always had this situation or if it started happening after I made changes. Truck is an 1983 60

I do have a weber carb....the truck actually runs great so I am not inclined to make any changes around that...just need to figure out the pressure in the tank.

 

[JTU]

Probably just need to replace your charcoal canister. That’s usually the cause of excessive tank pressure.

 

[BlackCat]

If you don’t have a charcoal canister as you say, where are the two lines to it going now?

 

[HemiAlex]

You’re desmogged. You don’t have a provision for a charcoal canister with the Weber.

If you got a JimC carb you could reincorporate that all.

 

[NeverGiveUpYota]

Weird that the CC was ditched in your desmog. Pretty sure you don’t have a Weber either correct?

 

[HemiAlex]

Weird that the CC was ditched in your desmog. Pretty sure you don’t have a Weber either correct?

I’ve got the city racer which has no ports for it.

 

[NeverGiveUpYota]

I have a city racer too but I still have my CC inline.

 

[HemiAlex]

I have a city racer too but I still have my CC inline.

I may be doing this wrong. Where do you pull the vacuum source from?

 

[NeverGiveUpYota]

I may be doing this wrong. Where do you pull the vacuum source from?

I have a T attached. I’ll get you a photo.....

 

[OSS]

The tank needs to vent somehow and currently your vent pipe is plugged. The Toyota gas cap has a one way valve built into it. It will allow air into the tank, but not out.
Cars in the 1960s and prior didn't have charcoal canisters. They vented their tanks directly to atmosphere, You can do the same thing. Find the vapor vent pipe and unplug it, You should be able to blow back through it and air should come out the fill neck. Then attach a length of fuel hose to it if needed and a small fuel filter to that and mount it up high in the engine compartment.
Or remove the gas cap and stuff a rag in the fill neck (redneck fix).
An overpressurized tank can split its seams and leak (which was the reason for the tank recall in the first place).

 

[John Staton]

The tank needs to vent somehow and currently your vent pipe is plugged. The Toyota gas cap has a one way valve built into it. It will allow air into the tank, but not out.
Cars in the 1960s and prior didn't have charcoal canisters. They vented their tanks directly to atmosphere, You can do the same thing. Find the vapor vent pipe and unplug it, You should be able to blow back through it and air should come out the fill neck. Then attach a length of fuel hose to it if needed and a small fuel filter to that and mount it up high in the engine compartment.
Or remove the gas cap and stuff a rag in the fill neck (redneck fix).
An overpressurized tank can split its seams and leak (which was the reason for the tank recall in the first place).

Where would I find the vapor vent pipe?? No idea where to even look. Pictures are always the best

 

[KeilOver]

John, can you post a picture of your set up? That might help in diagnosing your issue.

 

[NeverGiveUpYota]

Where would I find the vapor vent pipe?? No idea where to even look. Pictures are always the best

I looked through here but it’s your footwork now because it dawns on me I’m not the one having issues. .... This is your second bible to the fsm to always find parts diagrams then cross reference to Toyota parts deal for prices.
I find I can only search the site through my phone I get some sort of block via my desk top. If your truck is pre-85 adjust the year.

TOYOTA LAND CRUISER 60FJ60LG-KA - TOOL-ENGINE-FUEL - | Japan Parts EU

TOYOTA LAND CRUISER 60FJ60LG-KA

www.japan-parts.eu

 

[LAMBCRUSHER]

Pics will help. Also, use search to see what others have done regarding charcoal venting and desmog... plenty of pics and detailed how-tos. Check out my desmog thread... that’s, “my desmog thread” not my desmog thread... it isn’t mine... hth

 

[Lopott]

I went to a vented gas cap. bought from Napa. followed a link somewhere on here

 

[ceylonfj40nut]

I went to a vented gas cap. bought from Napa. followed a link somewhere on here

Others drill a small pilot hole on your fuel fill lid As an option.

 

[cheeese]

If you switch to the OE Toyota vented cap like I did, you might have some trouble getting the screw tabs to hold against the filler body. For some reason it doesn't hold as securely on my 84.

 

[John Staton]

I went to a vented gas cap. bought from Napa. followed a link somewhere on here

that sounds like the easiest solution. Was is a stant? did you get the part number from a thread or just have them look it up?

 

[OSS]

If you get a vented gas cap. Be sure to pack the empty space between the filler door and cap with a big rag if driving on dusty dirt roads. That little compartment gets filled with dirt after driving on dusty roads and the gas cap vent can suck in the dirt.

 

[Spike Strip]

Vented cap for both Pressure and Vacuum

Amazon product ASIN B000C5GAT8
Or drill a small (very small) hole