Excessive fuel tank pressure (2 Viewers)

[Summiteer]

Resurrecting this old thing but I feel it is relevant and better than starting anything new due to all the good info here. Just read through this whole thread hoping for a light at the end of the tunnel, I fear my tunnel is still dark. I replaced my CC with the VC120 and still get a strong fuel smell and pressure at the tank... Only in the summer and after giving the engine a good workout... not necessarily at high altitudes.

Seems like a lot of people with this problem have had good success with switching to the VC120. I'm curious if there is anyone out there like me that did the switch but still had the problem with excessive pressure and if they ever found a fix for it.

 

[Pitch]

I'm curious if there is anyone out there like me that did the switch but still had the problem with excessive pressure and if they ever found a fix for it.

I am in the same boat, same symptoms too. However, I do live at 7000 ft. All symptoms are drastically improved after the VC120 install, but I still get fumes when it is hot. The vacuum switching valve just downstream from the canister failed the tests outlined in the FSM, so I ordered a replacement (actually an FZJ80 replacement that I hope will work on my 3FE 80 since the 3FE part is discontinued). I will report back with results. I am still waiting for the part to arrive.

 

[retrofive]

IIRC the fuel cap could be faulty/failing as well.

 

[treerootCO]

I swapped out my charcoal canister with the Autozone one and haven't had an issue since.

https://forum.ih8mud.com/80-series-tech/412261-charcoal-canister-great-option.html

Never mind. The new fuel they sell us has some serious issues...

 

[inkpot]

Also could be the beginning of the infamous CRACKED TANK! Been a lot of them showing up

 

[thatcabledude]

Holy s*** treeroot.

 

[Summiteer]

Mine has been that bad once, freaked me out! shooting gas 20' from the cruiser.... Usually just vents for 5-10 minutes and smells like fuel the rest of the trip.

Checked the CC today, good. Checked the VCV per FSM, good. Checked gas cap, good. Line from tank to CC works both ways. Line from CC to VCV is good. Engine temp stays right around 194-196...

 

[MikeB]

Also could be the beginning of the infamous CRACKED TANK! Been a lot of them showing up

John, do you remember if the cracked tanks that you've seen show normal/excessive pressure at the cap? It seems like the crack might keep any pressure from building up.

 

[Timpanogos Slim]

huh, I had the burst of fumes when i removed the cap, would go on for 20 seconds or so, but no spitting.

Installed the autozone charcoal canister and never had a problem again, more than 3 years now.

Bad check valve on the canister maybe?

 

[inkpot]

John, do you remember if the cracked tanks that you've seen show normal/excessive pressure at the cap? It seems like the crack might keep any pressure from building up.

The "common" crack that we have seen is on the shoulder of the lower top section . Best guess us that it is due to over stressing a thin spot caused by a compound curve

 

[bryson]

My 96 with a ~1yr old VC120 is building pressure again... My 94 with the stock CC does it too. I'll pull the VC120 from the 96 and see if it's plugged. Anybody remember if the VC120 carries a warranty?

 

[Jeeper]

Anybody remember if the VC120 carries a warranty?

If purchased at Autozone, it carries their lifetime warranty. Let us know if it's actually plugged - haven't seen the VC120 do that yet. Would be good info.

 

[Pitch]

You can "flush" the canister with compressed air to get it flowing again.

 

[inkpot]

You can "flush" the canister with compressed air to get it flowing again.

Can't you do the same thing with the OEM units?

 

[Qball]

Get a new VC120?

 

[Pitch]

Can't you do the same thing with the OEM units?

Indeed! ...Not a permanent fix, but it will buy you time. This was taken from the FSM.

 

[LandCruiserPhil]

The only problem I found when rebuilding the stock unit is the valves on top getting sticky or stuck. The valves are about the only thing that can go wrong.

 

[BILT4ME]

Never mind. The new fuel they sell us has some serious issues...

Holy Crap! I was wondering what folks are REALLY talking about when they say their tanks are venting for 20+ seconds. I thought someone's timer is WAY off, but WTF? I've NEVER seen a vehicle puke gas out the filler neck before!

That being said, Just yesterday, I noticed I have a fuel smell coming from my truck. Tracked it down this morning and there is a leak from the tank somewhere. I will pull the fuel pump cover to see if it's just a hose, or if I have to dig deeper for a crack in the tank. I noticed the last 2 fill-ups that I never had ANY pressure buildup. Usually I would have one or two seconds of PFFFTTTHH, but that was it. I hope it's just a seal or a hose.

 

[inkpot]

Just take a mirror and a flashlight and check for wetness along the inboard side right where the top of the tank drops down, near the middle. John

 

[BILT4ME]

Just take a mirror and a flashlight and check for wetness along the inboard side right where the top of the tank drops down, near the middle. John

Thanks I'll do that!