Non ecm controlled charcoal canister
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Junior Member
Joined: Jan 2009
Posts: 87
Likes: 9
From: Merced ca
Car: 87 trans am gta /89 chevy corvette
Engine: 350
Transmission: Auto
Axle/Gears: 3.27 / 3.07
Non ecm controlled charcoal canister
Is it possible to install a non ecm controlled charcoal canister on a tpi car? Only reason I’m asking is I’m thinking about retaining it after swapping in the fitech tpi system. Thought about deleting it and venting. Seen all the other threads on it. More concerned about fuel smell than anything.
Joined: Apr 2010
Posts: 514
Likes: 44
From: New Jersey
Car: 87 Monte Carlo SS
Engine: 89 350TPI Transplant
Transmission: 2004r
Axle/Gears: 3.73
Re: Non ecm controlled charcoal canister
There were charcoal canisters on GM vehicles before ECMs came into use. If I remember correctly, my 1976 Camaro had a charcoal canister. No ECM just HEi large cap distributor. The canister had two ports on it. One port went to the fuel tank vent connection. The other went to a Temperature Vacuum Switch (TVS) installed in the intake manifold to sense coolant temps. The TVS was in between the carb and the canister. The TVS had three ports on it. One went to the canister. The second port was a vent and the other went to the Carb ABOVE the throttle blades. Being in that position, vacuum will increase with more throttle opening. Almost zero vacuum at idle. GM had to have it that way to ensure a smooth idle. You should be able to find these parts on Rock Auto for a 1976 Camaro 305 V8.
How it worked was that when the motor was cold the TVS would prevent the canister from venting fumes to the carb. After the motor was up to temperature, the TVS would open and connect the canister to the fuel tank vent line. But it would only suck fumes from the tank at speeds above idle because of the vacuum location being above the throttle blades.
Hope this helps,
Good Luck,
Fred
How it worked was that when the motor was cold the TVS would prevent the canister from venting fumes to the carb. After the motor was up to temperature, the TVS would open and connect the canister to the fuel tank vent line. But it would only suck fumes from the tank at speeds above idle because of the vacuum location being above the throttle blades.
Hope this helps,
Good Luck,
Fred
Last edited by Fred SS; Aug 24, 2025 at 03:34 PM. Reason: delete text
Thread Starter
Junior Member
Joined: Jan 2009
Posts: 87
Likes: 9
From: Merced ca
Car: 87 trans am gta /89 chevy corvette
Engine: 350
Transmission: Auto
Axle/Gears: 3.27 / 3.07
Re: Non ecm controlled charcoal canister
There were charcoal canisters on GM vehicles before ECMs came into use. If I remember correctly, my 1976 Camaro had a charcoal canister. No ECM just HEi large cap distributor. The canister had two ports on it. One port went to the fuel tank vent connection. The other went to a Temperature Vacuum Switch (TVS) installed in the intake manifold to sense coolant temps. The TVS was in between the carb and the canister. The TVS had three ports on it. One went to the canister. The second port was a vent and the other went to the Carb ABOVE the throttle blades. Being in that position, vacuum will increase with more throttle opening. Almost zero vacuum at idle. GM had to have it that way to ensure a smooth idle. You should be able to find these parts on Rock Auto for a 1976 Camaro 305 V8.
How it worked was that when the motor was cold the TVS would prevent the canister from venting fumes to the carb. After the motor was up to temperature, the TVS would open and connect the canister to the fuel tank vent line. But it would only suck fumes from the tank at speeds above idle because of the vacuum location being above the throttle blades.
Hope this helps,
Fred
Good Luck,
Fred
How it worked was that when the motor was cold the TVS would prevent the canister from venting fumes to the carb. After the motor was up to temperature, the TVS would open and connect the canister to the fuel tank vent line. But it would only suck fumes from the tank at speeds above idle because of the vacuum location being above the throttle blades.
Hope this helps,
Fred
Good Luck,
Fred
Senior Member
Joined: Jul 2016
Posts: 801
Likes: 213
From: az
Car: 91 WS6 GTA
Engine: 5.3
Transmission: 4l60e
Re: Non ecm controlled charcoal canister
https://www.summitracing.com/parts/tnk-fvc516
theres plenty of aftermarket set ups for eliminating fuel smells
theres plenty of aftermarket set ups for eliminating fuel smells
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