Gas Smell after Replacing Charcoal Canister (1 Viewer)

[DARKNESS]

I replaced my charcoal canister last week with the GM version (VC120) due to pressure in my fuel tank. I also replaced all the lines and clamps immediately connected to the canister. Finally, I drilled a hole in the bottom of the canister plate and reused the OEM hose that vents the vapors into the frame like many others have done. That solved the tank pressure issue. My old canister was very difficult to blow through and when I opened it up the charcoal reeked of gasoline and the filters were pretty dirty. I plan to refurbish it and keep it as a spare.

Unfortunately, after driving to work and back yesterday, I noticed that the garage had a strong gasoline smell after I had parked for an hour or so. I could not locate a part of the vehicle where the smell was coming from, but I assume it was being vented out of the charcoal canister into the frame.

I think this means that there is something else wrong with the system. My first guess is that vapors aren't being pulled from the charcoal canister while the engine is on. Perhaps this is what caused the original canister to become saturated and go bad? It seems like if this is the case there could be a number of culprits (VCV, Check Valve, and VSV). I know the FSM has tests for these valves, but they look like a PITA to get remove. I have no check engine codes to go on.

So, before I remove the valves and test them, I figured I'd ask if anyone has had this issue before and solved it. I've seen a few threads with this problem mentioned, but nobody came back with a solution.

 

[inkpot]

If you keep the pressure in, then the smell stays in. If you let the pressure out, then the smell gets out too. They are one and the same. John

 

[DARKNESS]

I have a '99 Tacoma and it doesn't have a pressurized tank or smell like gasoline. Neither did my '01 GTI, my wife's old Xterra, her Outback or my '93 Saturn. I thought the whole point of the charcoal canister was to recover those vapors? Obviously the system can't be perfect, but it's at least good enough on every other vehicle I've owned, both older and newer.

 

[MLX450]

" Finally, I drilled a hole in the bottom of the canister plate and reused the OEM hose that vents the vapors into the frame like many others have done."

I did not drill a hole in the bottom of the VC120. I just connected the 2 top hoses and left the bottom disconnected. So far no venting at the tank and no gas smell.

 

[diego355]

I drilled the bottom of mine but just the cap not the actual canister

 

[DARKNESS]

Possible, but all that does is change the vent location. Unless it changes the rate at which it vents which affects the fuel content of the vapor. However, others have done what I did with seemingly no problems.

 

[DARKNESS]

I only drilled the cap as well.

 

[l1coeea9]

Same here. No drilling holes and no smell of gas. And, it fixed the pressure issue in the fuel tank.

 

[DARKNESS]

Well, the smell seems to have gone away. Maybe the canister had to equilibrate for awhile or something?

 

[mod5csi]

Im about to install a VC120 in my 96. Could be the altitude. Im in Parker not far from you.

I thought I read somewhere that the altitude affected this mod.

 

[Rusco]

Interesting.... I just finished putting the GM canister in mine, no mods to the canister at all, and my gas smell on shut-down, warm days, went away.

 

[landtoy80]

I just ran about 3/4 the way up Transfer Trail in Glenwood Springs, CO and my CC was making a bubbling noise and the smell was awful. Wife was getting a nasty headache. That trail has a pretty good incline, temp was about 80 deg F, a/c on full blast, 3/4 tank of Shell 85 octane, in low gear and low gear in low range. I checked the vacuum to the CC and it starts getting vacuum at 1700 rpms.

Getting an AutoZone VC120 tomorrow and will try the trail again and see what happens.

 

[DARKNESS]

That will probably fix it. I actually just refurbished my old canister to see if I could do it. Seems to be working pretty well. It's not very hard to do and only costs $15 for new charcoal.

 

[landcrshr]

Have you got a write-up on replacing the charcoal?

 

[DARKNESS]

At the end of Firstoy's writeup:

https://forum.ih8mud.com/80-series-tech/239299-charcoal-canister-modification-need-help-3.html

He pioneered it, but I think my method is cleaner and can be done repeatedly on the same canister easily.

 

[Overland Tailor]

I changed mine as well and it solved the issue for normal driving around town. No more pressure, no more smell.

Took the kids yesterday and crawled for about 7 miles in low at no more than 5 mph... Slow going over rough terrain. Temp was 92*, ac going for the little princess's and went from 600' AGL to over 1800' AGL.... Started smelling fuel and found constant pressure in the tank.

I'm sure at that slow pace I was just returning boiling fuel to the tank for over an hour.

Not sure anything is going to help in that situation.. Maybe the stock canister in perfect condition would have done the same???


Thoughts??


Thanks,

John

 

[coax]

I think this means that there is something else wrong with the system. My first guess is that vapors aren't being pulled from the charcoal canister while the engine is on. Perhaps this is what caused the original canister to become saturated and go bad? It seems like if this is the case there could be a number of culprits (VCV, Check Valve, and VSV). I know the FSM has tests for these valves, but they look like a PITA to get remove. I have no check engine codes to go on.

So, before I remove the valves and test them, I figured I'd ask if anyone has had this issue before and solved it. I've seen a few threads with this problem mentioned, but nobody came back with a solution.

I think you are on the right track. The charcoal cansiter is only half the equation. It can store a given amount of fuel vapor, but relies on the rest of the system to put a vaccum on it, pull the vapor out and combust it during certain situations when the engine is running.

If those components are not working (or not working enough) then eventually the vapor would get purged out the bottom of the canister.

I recently replaced my canister with the vc120, if that doesn't do the trick then I've gotta test other components. Seems like the FSM has a good proceedure, but like you state, some of those components are not the easiest to get to.

 

[jatree]

Following - I had an EGR Vacuum Modulator issue and wasn't detecting the strongest vacuum on top of the intake manifold (or was it the TB with the little ports) so even though I just replaced with a VC120, think there might be more to the equation. My VSV and EGR tested fine so perhaps there's just a clog somewhere or I need to repeat the tests and make sure vacuum is in the right places...

 

[60wag]

Bump to top. I've had the VC120 can in my 80 for while. It worked great for the first few years but now reeks of ethanol. I'm going to check for loose hoses/fittings and then move on to checking the purge valves, etc. Anyone found defective devices in the purge system yet? TIA