Charcoal Canister - Great Option! (3 Viewers)

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The bottom of the canister pops off and you will see how far you have to drill..however there is no point in drilling it if you don't tape the lower circumference vent closed.

You should just drill it with the bottom part removed anyway.
 
All -

After owning my 80 for over 2 years, experiencing higher than normal pressure when removing the gas cap the entire time, I tried many solutions. However, I've been reluctant to replace the charcoal canister due to the cost -- approx $300 (plus or minus), and it's a dealer-only item.

Many of us have posted/read info on this thread:
Excessive fuel tank pressure

I tried a junk yard canister from a 1997 80 with absolutely no affect. I tested hoses, attempted to test pressures, made sure the VSV worked correctly, etc. As best I could tell the system was at least functioning.

After much research, I found this alternative canister for $36 !!!
If the link gets stale, it's Autozone part VC120 for early 1990s GM cars with the 3.1L V6 (pontiac, oldsmobile). The dimensions were close enough to ours, so I pulled the trigger on a hunch. And it works beautifully! I wanted to run thru several fill-ups before I posted, and I can say that after 6 fill-ups, my 80 finally operates like a normal car (as the gas pump anyway). No sound, no air escaping, etc.

It has the same style connectors and pulls in fresh air from the bottom just like the 80s. Using the highly calibrated "blow with your mouth" technique, I confirmed that this canister is almost identical to the stock 80s as described in the FSM. Minor details on mounting:

  • There is no hose connection on the bottom like the 80s, so you can remove the hose completely. This replacement canister has it's own filter and cover on the bottom. In stock 80s, the hose simply routes down to the frame area. I assume to pull in fresher, cooler air.
  • The diameter is just a bit larger than the stock 80s, but you can see in the pic below that it fits in the stock bracket, in the stock location, using the stock hoses. You'll notice that I used a ziptie in place of the bolt on the bracket - a longer bolt would be better, but I didn't have one around. And it's a tight fit, so I don't think it's going anywhere
  • The "tank" port on the canister uses a larger diameter hose barb, but a little persuasion works.
Info/links:
How to test your canister from 1997 FSM
-I suspect that the purge check valve in my canister was sticking. You should have suction into the engine on the purge hose as described in the link above. This suction should be able to keep up with vapors generated in the tank as long as the canister flows freely.


lc_cnstr.jpg


I haven't tested this after driving up to high elevations yet, but based on my experience so far, I think it's going to do great. Hope this helps out the community as much as it's helped me.


Just put this in my FJ80 and lo and behold the gas pressure issue I have been having is no more - thank you!!!!!!
 
Cant get the Part VC120 From Autozone.. they discontinued?
A little google search netted me the application for this part for a 1997 PONTIAC GRAND PRIX GT 3.8L 231 cubic inch V6 MFI ? Can anyone confirm any other part numbers and results?
Just ordered one yesterday from Auto Zone. VC120 in stock, $50.
 
It worked for the gas smell on mine (however not completely eliminated) but recently I drove 5 hrs up the NC mountains and the pressure issue returned at the pump albeit not as bad.
Around town no issues with hissing at the pump when I take off the cap.
I recommend trying the canister and check for gas leaks.
It seems to be a common problem.
Are you driving an 80 or is that your rig in the pic?
 
This may be of use... Another tail tail sign for me was gas drippings from a full tank. After dropping the tank, I noticed a very small crack on the top side of the tank where three different surfaces meet. My theory is that this crack was cause by repeated cycles of buckling of the tank when the pressure built up, and release of the pressure when I filled the tank. Over time, this weak spot in the metal just cracked.

If you are smelling gas even when the cap is closed, then check under the car and around the tank. If it smells of gas or if it's wet, then check the top side of the tank for a crack.

I could not find anybody who was willing to weld the hole, so I found a good used one in a junk yard. VERY expensive.
 
Just ordered one yesterday from Auto Zone. VC120 in stock, $50.
I couldn't get one today at AutoZone and ordered one from NAPA from the Delco numbers. It will likely be about $70 when the dust clears. Just came back from Colorado and Utah, my auxiliary gas tank was having real problems being pumped to primary tank. It seems to be working at near sea level. I wonder if the increased pressure was too much for the inline pump to function. When opening the gas cap at 7,000 feet, it seemed like a bunch of demons were coming out for a couple of minutes.
 
For one friend replacing it fixed the issue. For another friend it didn’t make a difference.
 
Worked for mine. But I had my fingers crossed when I installed it.
 
Worked for mine. But I had my fingers crossed when I installed it.

I can confirm this is key. I also crossed my fingers when I installed and have been issue free for over a year.
 
For one friend replacing it fixed the issue. For another friend it didn’t make a difference.
Were you experiencing any “old gas” smells while idling? I have that issue also and I don’t know if the two are related.
 
Were you experiencing any “old gas” smells while idling? I have that issue also and I don’t know if the two are related.
Mine has never had the issue but I did replace the CC before driving at high altitudes. I don’t recall either of the other guys mentioning anything about old gas smell, just the often reported venting when the fuel cap is removed
 
Just got mine for $41 sent to my door with coupon code ALLSTATE.

EDIT: $44.36 after tax.
 
Last edited:
All -

After owning my 80 for over 2 years, experiencing higher than normal pressure when removing the gas cap the entire time, I tried many solutions. However, I've been reluctant to replace the charcoal canister due to the cost -- approx $300 (plus or minus), and it's a dealer-only item.

Many of us have posted/read info on this thread:
Excessive fuel tank pressure

I tried a junk yard canister from a 1997 80 with absolutely no affect. I tested hoses, attempted to test pressures, made sure the VSV worked correctly, etc. As best I could tell the system was at least functioning.

After much research, I found this alternative canister for $36 !!!
If the link gets stale, it's Autozone part VC120 for early 1990s GM cars with the 3.1L V6 (pontiac, oldsmobile). The dimensions were close enough to ours, so I pulled the trigger on a hunch. And it works beautifully! I wanted to run thru several fill-ups before I posted, and I can say that after 6 fill-ups, my 80 finally operates like a normal car (as the gas pump anyway). No sound, no air escaping, etc.

It has the same style connectors and pulls in fresh air from the bottom just like the 80s. Using the highly calibrated "blow with your mouth" technique, I confirmed that this canister is almost identical to the stock 80s as described in the FSM. Minor details on mounting:

  • There is no hose connection on the bottom like the 80s, so you can remove the hose completely. This replacement canister has it's own filter and cover on the bottom. In stock 80s, the hose simply routes down to the frame area. I assume to pull in fresher, cooler air.
  • The diameter is just a bit larger than the stock 80s, but you can see in the pic below that it fits in the stock bracket, in the stock location, using the stock hoses. You'll notice that I used a ziptie in place of the bolt on the bracket - a longer bolt would be better, but I didn't have one around. And it's a tight fit, so I don't think it's going anywhere
  • The "tank" port on the canister uses a larger diameter hose barb, but a little persuasion works.
Info/links:
How to test your canister from 1997 FSM
-I suspect that the purge check valve in my canister was sticking. You should have suction into the engine on the purge hose as described in the link above. This suction should be able to keep up with vapors generated in the tank as long as the canister flows freely.


lc_cnstr.jpg


I haven't tested this after driving up to high elevations yet, but based on my experience so far, I think it's going to do great. Hope this helps out the community as much as it's helped me.
Out of curiosity is it possible that the hose that comes off the bottom (to take in fresh air) is clogged?
 

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