Charcoal Cannister Valve

[Nolan Sylvester]

Anyone ever just replace the valve on their charcoal canister. I just did that and it seems as though it has fixed the problem. I paid $60 dollars for the valve and so far the check engine light has stayed off? I was just wondering if anyone else has taken this route vs replacing the whole thing?

 

[Live to Ski]

Um, what year rig are you running?

 

[Nolan Sylvester]

2005

 

[Spike555]

On the Corolla I had (1998) I kept getting a MIL for the EVAP canister being bad, I replaced the purge valve and that solved the problem.
Basically if the EVAP canister can't be emptied by the fumes being sucked into the engine it is going to become full and cause a MIL.

 

[Nolan Sylvester]

That is exactly what I did. Light stayed on a few days but now has been off almost a week. Hoping it solved the problem. Sure was a lot cheaper!

 

[Live to Ski]

Nolan: what problem were you having?

 

[Nolan Sylvester]

Just had check engine light and evaporated code mechanic was able to check all valves except on charcoal canister so he recommended if I can find one and replace it, should solve problem without replacing $500 canister.

 

[PabloCruise]

Nice work! Is '05 can in the back?

 

[Live to Ski]

write up?

Does this valve have any relation to the charcoal cannister/gas tank pressure issues on the "above spare canister" rigs?

 

[bluesquirrel]

I have to replace this valve on my 98. Will let u know if it clears up my codes. I'm thinking it will, because of the code

 

[SierraWheeler]

Have experienced issues with very high fuel tank pressure. Started out on the first few trips as fuel vapors hissing from the charcoal canister that we could smell inside the cab. It was worrying, but in a "hm, that's odd" sort of way. On the last trip, pressure in the fuel tank broke the seal on the fuel cap. I actually noticed because I could see fuel vapors exiting the closed fuel lid in the side mirror. When I stopped, the smell was really bad and there was fuel was leaking down the side of the truck. I decided it was probably better to crack the cap and vent while I could monitor the situation then to roll down the rest of the trail with fuel bubbling out of the cap. Took maybe 30 minutes of slow venting to release most of the pressure, all the while I was thinking of the land cruiser that recently burnt to a crisp from what I can imagine was some sort of similar issue with excess fuel tank pressure.

I followed diagnostic flow chart in the FSM and although I didn't have all of the expensive tools to properly diagnose I am pretty sure it is a failed evap (purge) VSV which didn't allow the pressure in the charcoal canister to purge to the engine. I am assuming that after several trips the pressure finally found the weakest link and broke the seal to the fuel cap. Unfortunately when the evap VSV fails, the FSM also recommends replacing the charcoal canister which includes a new vapor pressure VSV. Not a bad idea in my case, the walls of the old charcoal canister were visibly ballooned and I worry that both the vapor pressure VSV and some of the internal valves in the canister could have been damaged by the pressure. Ordered both evap VSV and charcoal canister along with a new gas cap. My cruiser always smelled like gas when I parked in the garage, so I assume my charcoal was shot and hoping this solves both problems. Major ouch to the tune of nearly $700.

FWIW I never had a CEL... Fingers crossed that the new parts fix the issue... the only other culprits in the FSM are either the vapor pressure sensor or the ECM, both of which are unlikely and even more unnecessarily expensive.

 

[2001LC]

Have experienced issues with very high fuel tank pressure. Started out on the first few trips as fuel vapors hissing from the charcoal canister that we could smell inside the cab. It was worrying, but in a "hm, that's odd" sort of way. On the last trip, pressure in the fuel tank broke the seal on the fuel cap. I actually noticed because I could see fuel vapors exiting the closed fuel lid in the side mirror. When I stopped, the smell was really bad and there was fuel was leaking down the side of the truck. I decided it was probably better to crack the cap and vent while I could monitor the situation then to roll down the rest of the trail with fuel bubbling out of the cap. Took maybe 30 minutes of slow venting to release most of the pressure, all the while I was thinking of the land cruiser that recently burnt to a crisp from what I can imagine was some sort of similar issue with excess fuel tank pressure.

I followed diagnostic flow chart in the FSM and although I didn't have all of the expensive tools to properly diagnose I am pretty sure it is a failed evap (purge) VSV which didn't allow the pressure in the charcoal canister to purge to the engine. I am assuming that after several trips the pressure finally found the weakest link and broke the seal to the fuel cap. Unfortunately when the evap VSV fails, the FSM also recommends replacing the charcoal canister which includes a new vapor pressure VSV. Not a bad idea in my case, the walls of the old charcoal canister were visibly ballooned and I worry that both the vapor pressure VSV and some of the internal valves in the canister could have been damaged by the pressure. Ordered both evap VSV and charcoal canister along with a new gas cap. My cruiser always smelled like gas when I parked in the garage, so I assume my charcoal was shot and hoping this solves both problems. Major ouch to the tune of nearly $700.

FWIW I never had a CEL... Fingers crossed that the new parts fix the issue... the only other culprits in the FSM are either the vapor pressure sensor or the ECM, both of which are unlikely and even more unnecessarily expensive.

Be interesting if you'd replace one component at a time, and note any changes/improvments.

 

[PabloCruise]

Have experienced issues with very high fuel tank pressure. Started out on the first few trips as fuel vapors hissing from the charcoal canister that we could smell inside the cab. It was worrying, but in a "hm, that's odd" sort of way. On the last trip, pressure in the fuel tank broke the seal on the fuel cap. I actually noticed because I could see fuel vapors exiting the closed fuel lid in the side mirror. When I stopped, the smell was really bad and there was fuel was leaking down the side of the truck. I decided it was probably better to crack the cap and vent while I could monitor the situation then to roll down the rest of the trail with fuel bubbling out of the cap. Took maybe 30 minutes of slow venting to release most of the pressure, all the while I was thinking of the land cruiser that recently burnt to a crisp from what I can imagine was some sort of similar issue with excess fuel tank pressure.

I followed diagnostic flow chart in the FSM and although I didn't have all of the expensive tools to properly diagnose I am pretty sure it is a failed evap (purge) VSV which didn't allow the pressure in the charcoal canister to purge to the engine. I am assuming that after several trips the pressure finally found the weakest link and broke the seal to the fuel cap. Unfortunately when the evap VSV fails, the FSM also recommends replacing the charcoal canister which includes a new vapor pressure VSV. Not a bad idea in my case, the walls of the old charcoal canister were visibly ballooned and I worry that both the vapor pressure VSV and some of the internal valves in the canister could have been damaged by the pressure. Ordered both evap VSV and charcoal canister along with a new gas cap. My cruiser always smelled like gas when I parked in the garage, so I assume my charcoal was shot and hoping this solves both problems. Major ouch to the tune of nearly $700.

FWIW I never had a CEL... Fingers crossed that the new parts fix the issue... the only other culprits in the FSM are either the vapor pressure sensor or the ECM, both of which are unlikely and even more unnecessarily expensive.

$700?!? Ouch..

Be interesting if you'd replace one component at a time, and note any changes/improvments.

This ^^^

Sounds like the gas cap needs fixing pronto, but maybe replace the VSV before doing the charcoal can?

 

[SierraWheeler]

Yeah, I will take you guys up on that suggestion and replace gas cap / evap VSV first. I'm still worried about the old charcoal canister and vapor pressure VSV but I don't think the new evap VSV would get damaged in the process of testing either of those. If only replacing the evap VSV doesn't fix the pressure issue then the new gas cap might get fried, but that is only like $20 so no biggie. I think I'll carry the extra canister around in my drawers for now just in case I experience another failure on the trail...

 

[2001LC]

I'd replace the canister if it swelled up. It just be interesting to see improvements one part at a time.

 

[bluesquirrel]

I replaced the valve in my '98, and after the drive cycle, the CEL is back on for the same codes.
P0440
P0441
P0446

 

[bluesquirrel]

Now replaced the vacuum switch on top of the canister. Vacuum lines are pretty old, so I am waiting on the lines to replace them all.

If still a problem, I'll replace the canister, and maybe drop the tank and start replacing things back there

 

[SierraWheeler]

^Just a heads up, my oem replacement canister came with a new vapor pressure VSV and a new vapor pressure sensor.

I ended up wimping out and just following the FSM instead of trying to replace items one at a time for the sake of science. Replaced the evap VSV and canister assembly at the same time so all of my sensors, valves, and canister are new. No issues yet but I haven't really had a good test of the new system. Used to happen the worst when wheeling on warm days. It is wintertime so temperatures are lower and my favorite wheeling routes are snowed over for the season.

 

[Live to Ski]

So, for us "under the spare tire" rigs, wonder if we could do a temp rerouting to an "under hood" config.

Anticipate that this might cause the "visual" biannual Cali smog penalty flag to be thrown However, if made to be easily removed prior to smog (with the original under spare canister back in action), then reinstalled after smog, might eliminate the overpressure/altitude/temp problem.

Just thinking...;....

 

[bluesquirrel]

After replacing the vapor pressure vsv and all the vacuum lines associated with the system, I have no more CEL codes. A couple of the vacuum lines were very loose, and one of them was the likely culprit of a transient fuel smell.

I remember it was asked about, but I have not noticed any difference in engine behavior.