Charcoal Canister

[MKPNG]

I am getting quite a bit of pressure build up in my fuel tank. From what I have read on here so far, this is due to a bad charcoal canister. Is there a way to verify that, or is that really one of the only things it could be?
Also, I saw somewhere else on here that there was a GM charcoal canister that fit the 80 series and was much cheaper. If this is the case, can someone direct me towards what it is? Thank you!

 

[newtomelx]

Autozone vc120

 

[mydogsmonkey]

Autozone vc120

this. and you can test it by blowing through it, there is a procedure listed in the FSM and can be found with minimal searching. I just tested and replaced mine a few months ago.

Gas Smell (Charcoal Canister)

Charcoal Canister - Great Option!

 

[MKPNG]

checking VCV operation (hose connects between purge port on canister and VCV)

• on COLD engine, disconnect purge hose and check for NO air suction at idle and 3000rpm
• on HOT engine, disconnect purge hose and check for NO air suction at idle, but it SHOULD have suction at 3000rpm

I am still very new to actually working on my truck, but I learn fast.
What is the VCV he his talking about in this post?

 

[grizzlygibbs]

I have one for sale in the classifieds. Yes, the vc120 is a replacement that many use, but it's slightly larger. I decided to go a different route and mine is brand new.

 

[DARKNESS]

I think the only way your fuel tank will stay pressurized like that is if the check valve in the charcoal canister itself is stuck. Replace it with the VC120 and you'll be good to go. Its cheap and easy.

I think they mean VSV not VCV. VSV is vacuum switching valve. If you're new to working on your truck, then get a factory service manual (FSM) if you haven't. It has a good section that will walk you through troubleshooting the evap system.

For Sale: - 40, 50, 60, and 80 series FSM for a hell of a price.

 

[n00g7]

I have this problem (is it a problem?) -- should I replace as well?

Vents for a few seconds when I take off the cap to fill.

 

[120mm]

I have this problem (is it a problem?) -- should I replace as well?

Vents for a few seconds when I take off the cap to fill.

For $50, YES!

 

[n00g7]

For $50, YES!

Ordered. Know what PN for that hose? Mine are pretty crispy.

 

[120mm]

Ordered. Know what PN for that hose? Mine are pretty crispy.

I don't. But you want fairly supple hose, especially since one of the VC120 barbs is slightly oversize and it takes man hands and some lube to get it on.

 

[n00g7]

Thanks, I'll go on the hunt after the part comes.

 

[MKPNG]

Ok, so now I know I need to replace the canister. How pressing is this for me to do? Do I need to do it right away? What are the implications if I don't?
I am on a tight budget.

 

[JCAZ]

I had the same issue for several years in my 96 LX450. Every summer here in Arizona the tank would have excessive pressure. I too like many replaced the canister with the Auto Zone model. This did not help. I also replaced the fuel filler neck, gas cap and had the dealer check the system. About a month ago with temperatures in the 90's I had the pressure issue again to where the garage would fill with vapors. After reading some articles on the fuel system, I decided to replace the fuel pressure regulator that sits on the fuel rail. Since replacing this I have not hadf an issue. No pressure or fuel smell what so ever.

 

[n00g7]

How much pressure is excessive? Any? Or is some slight pressure normal?

 

[Wayne]

The check valve in the OEM canister is set to open at 1 psi. So, with that, I'd say > 1 psi is too much. There's usually two issue with the OEM canister, 1) the check valve stick closed not allowing the fuel tank to vent, and 2) the charcoal gets saturated with fuel and is unable to filter the vapors (usually caused by over filling the gas tank). There are a few of us that have opened up the OEM canister, cleaned the check valve and refreshed the charcoal with new. There are threads on here detailing on how to do it.

 

[n00g7]

The check valve in the OEM canister is set to open at 1 psi. So, with that, I'd say > 1 psi is too much. There's usually two issue with the OEM canister, 1) the check valve stick closed not allowing the fuel tank to vent, and 2) the charcoal gets saturated with fuel and is unable to filter the vapors (usually caused by over filling the gas tank). There are a few of us that have opened up the OEM canister, cleaned the check valve and refreshed the charcoal with new. There are threads on here detailing on how to do it.

I have the Autozone part and the factory one, I need to get tubing as that's crispy and then I'll figure out which way I want to go. Assuming I have a bit over 1 psi... it's getting dealt with just when is the issue over everything else that needs to happen to the truck.

 

[woodsman 44]

I just did the VC120 from autozone, it was $60 OTD with cali tax

I just kept on the top bracket as well, its all you need with not much weight to it, its plastic, with a 2.5" bolt and your ready to go....

 

[n00g7]

I just did the VC120 from autozone, it was $60 OTD with cali tax

I just kept on the top bracket as well, its all you need with not much weight to it, its plastic, with a 2.5" bolt and your ready to go....

Where'd you get the new lines?

 

[woodsman 44]

Got em at local Napa parts store

 

[n00g7]

Got em at local Napa parts store

Ugh. Way too much effort over Amazon.