Fuel tank over pressurizing (1 Viewer)

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Spook50

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I think this is related to the fuel smell that I had noticed a short while back (which I hadn't noticed since then, so that's kind of odd), but the other day I saw sings of fuel getting past my filler cap and out underneath the fuel door on my 62. I checked the cap and it still has a good gasket and nice tight fit, but yesterday when I went to fill up, my tank was so highly pressurized that the damn cap nearly shot out of my hand when I removed it. Could this be a sign of a problem with that black manifold behind the cargo panel, or something to do with the charcoal canister? And whichever it is, is there an easy fix for it?
 
find the line that goes from vapor seperator to charcoal can and disconnect it on both sides; blow clear with air. test VCV on charcoal canister to verify it functions. test charcoal canister. if clogged you can swap lines- I had zero luck with that. or you can cut it open and refill it with aquarium carbon to factory fill level after shaking and packing it down a bit to minimize air pocket volume to carbon surface area and glue the lid back on with jb weld. been working for me for a couple/few months now. I cut the bottom half of the rolled lip off careful like with a zip-off wheel and pryed the top off gently with a paint can opener. keep track of disk orientation/order and factory fill level...
 
might also blow 4-5psi air thru the individual tank to vapor seperator lines with the cap off to make sure they're clear too....
 
Yup, this seems to be a common ailment for the 6x. Experienced the same symptoms ruining my new paint under the fuel door. Did everything Crusher did except opening the canister. The FSM has the steps for checking canister etc.

There's a few good threads already on this topic.
 
This topic really should be placed on the FAQ, it pops up all the time!

@LAMBCRUSHER, how did you cut it open? I spent a few minutes trying to figure out the best approach, in the end decided not to mess with it.
 
Pressure builds in the tank because the evap system is clogged somewhere, usually at the check valve in the charcoal can. Switching the lines on the top of the can usually solves it, unless the can itself is clogged. I put a vented gas cap on that's for pressure and vacuum.
 
The whole FJ60/62 gas tank recall fiasco was caused by the check valve in the charcoal canisters sticking... which over pressurizes the gas tank... causing weak seams to leak.

But since that check valve is a EPA smog component requirement, it had to stay. Toyota apparently decided that it was better to fix the symptom (leaking gas tanks) than the cause (sticking check valves) perhaps because there is no way to make a reliable cc check valve.

Its an emissions requirement to keep the fuel from constantly evaporating out of the gas tank when the car is parked.

The other port in the char can, the purge port, doesn't have a check valve and will flow freely through the carbon... out through the bottom.

The char can itself isn't going to plug up and block all air flow. And it can easily be purged with a little low pressure, pressurized air.
 
If you dig through, there was a thread a few years back about a readily- available canister that could be made to work pretty easily.

t
 
I've had a couple of canisters now that were totally occluded. I tried purging low and high pressure. Saturating with various solvents and purging. Couldn't even get the check valve to free up. Never took one apart as I thought it wasn't worth the effort.

Not my pic, but I did like this guy with the aftermarket canister just to control the stank. Last time the smog tech gave it the fish eye, but I didn't say anything and he moved on to the test.

http://www.autozone.com/1/products/243912-vapor-canister-vc120-duralast-vc120.html

charcoal.jpg
 
This is now apart of the FAQ's page. If you guys will help find relevant threads that we can add to this it would be great. I'll do some searching also.
 
This is now apart of the FAQ's page. If you guys will help find relevant threads that we can add to this it would be great. I'll do some searching also.

NIIIICE. For me, the clogged canister led to a fuel pump failure, so this is a great topic to include in the FAQ's. Cheers!
 
Can we start a new thread, "suggestions for the FAQ" ?
 
PM me what you'd like to see.
 

Thank You...and finally, some pics!
IMGP3290.JPG

this pic shows the bottom half of the rolled lip separated from the upper half of the rolled lip. I used a cut-off wheel on a 4 1/2" angle grinder to do this- only cut thru the outer skin of the lip!!!
IMGP3290.JPG
IMGP3293.JPG
IMGP3293.JPG

prying the top off...
IMGP3294.JPG

the beans...
IMGP3296.JPG

at the top; showing cap, spring, metal perferated disk, and fiber disks- one at top, one at bottom. this can had ONLY the fiber disk on the bottom of the fill...no pics of reassembled part, but some jb weld added BEFORE final seating of the cap would prolly make finishing the job nice and clean. I applied my JB weld after, and it was not as clean as I had hoped, but still clean enough to prolly not draw a techs attention and to be functional. the fill was just about topped out after some shaking and tamping so the spring was almost all the way compressed after assembly- based upon rough measurements; about 1/2" below the top to top of carbon...get the half gallon size of carbon and there will be just a bit left over. HTH
 
Wow!

That canister really amounts to nothing more than an oversized premium oil filter housing. There really isn't anything to it.

At least now we know that Toyota charged a fair price for it when it was available.

image.jpeg



The cc for the 200 series cruiser costs over $600. Tee hee.
 
I've got some problems with my tank over pressurizing also. I've also got a fuel leak with the tanks inlet outlet tubes which is causing my leak. While I drop the tank for the leak repair I'm going to check all the components for proper operation. I want this system to operate as designed.
 
why not? Just use a different type of glue...and don't destroy the sensor. of course, by then, they prolly manufacture the sensor with a FB loop and device ID with production datestamp coding. they could just stop trying to sensor us shade trees out of the market by banning DIY mechanics altogether, no? just one step closer to skynet, is all...
 

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